Pence heads to Seoul; NATO troops set up in Lithuania; Friendly fire kills 18 in Syria; Big bomb levels ISIS tunnels in Afghanistan; and just a bit more...

Vice President Mike Pence heads to Seoul while many expect a nuclear test from North Korea by the end of the weekend. Pence is scheduled to depart on Sunday, a day after North Korea marks its biggest national day, the Day of the Sun, the 105th anniversary of the birth of state founder Kim Il Sung, Reuters reports. Said one U.S. official to Reuters: “The White House has contingency plans for Pence's trip should it coincide with a another North Korean nuclear test by its leader Kim Jong Un.”

On Pence’s planner for this 10-day trip, his first as VP: Intentions to "talk about the 'belligerence' of North Korea at stops in Tokyo, Jakarta and Sydney, [a] White House adviser said. But the need for 'free and fair trade' will also be a theme."

Meanwhile, China says tensions in North Korea have to be stopped before reaching an “irreversible” stage. “We call on all parties to refrain from provoking and threatening each other, whether in words or actions, and not let the situation get to an irreversible and unmanageable stage," Chinese Foreign Minister Wang Yi told reporters in Beijing this morning. More here.

Also: Air China has reportedly stopped flights to Pyongyang.

The U.S. Air Force staged an “epic no-notice Elephant Walk” at the Kadena Air Base in Japan on Wednesday, The Aviationist reported Thursday. Involved: U.S. Air Force 44th and 67th Fighter Squadron F-15 Eagles and 961st Airborne Air Control Squadron E-3 Sentries.

Context: “‘Elephant Walks’ are particularly frequent in South Korea where local-based U.S. Air Force jets (often alongside Republic of Korea Air Force planes) frequently stage such ‘collective shows of force’ in response to North Korea’s aggressive posture and threats,” Aviationist writes. “Considered the current state of the relations between Washington and Pyongyang, with a U.S. Navy Carrier Strike Group heading to the Korean Peninsula, and several aircraft (including the WC-135 'nuclear sniffer') amassing not far from North Korea, it seems to be quite likely that the Elephant Walk at Kadena Air Base was just a way to showcase U.S. Air Force 18th Wing’s ability to quickly generate combat air power in the event of an attack on Kadena, the largest U.S. military installation in the Indo-Asia-Pacific region, and flex the muscles against Kim Jong Un and his nuclear plans.” Photos and more, here.

Back in Washington, reporters asked President Donald Trump whether the big bomb dropped in Afghanistan (more on that below) was sending a message to Pyongyang. "I don't know if this sends a message to North Korea," Trump replied. "North Korea is a problem, the problem will be taken care of." Via AFP, here.

From Defense One

In Lithuania, NATO Troops Set Up Near A Potentially Hostile Border // Magnus Nordenman: Just two years ago, it would have been nearly unthinkable for the Western alliance to set up a battalion here, some two hours' drive from Russia.

Remember When Mike Pompeo Loved Wikileaks? // Patrick Tucker: Now the head of the CIA wants to get tough on the "non-state hostile intelligence service." That won't be so easy.

Global Business Brief // Marcus Weisgerber: 3D-printing ICBM parts; shutdown countdown; Boeing stands up venture arm; and a lot more.

Trump Wants to Overhaul Federal IT, But He's Missing the People Who Could Help // Joseph Marks: Trump's prepping big plans to modernize and secure government technology, but he'll need government's buy in to get it done.

Trump Blew It at His China Summit // Michael H. Fuchs: The U.S. president's performance last week suggested to his Chinese counterpart that he is all talk, and can be pushed around with subtlety and patience.

The President Is Preventing the Foreign-Policy Debate America Needs To Have // Stephen Sestanovich: He promised to do both more and less abroad, but his frequent reversals and missteps are derailing efforts to choose one path.

Small Business Advocate Hauls Pentagon Into Court // Charles S. Clark: The plaintiff says the Defense Department is covering up ways in which large contractors hog work intended for smaller companies.

Welcome to this Friday edition of The D Brief by Ben Watson and Bradley Peniston. #OTD1988: The frigate USS Samuel B. Roberts nearly sinks after hitting a thousand-dollar Iranian naval mine. The crew fights fires and flooding to save the ship, which ultimately requires $96 million in repairs. Send us your news:

Trump bolsters the American troop presence in Somalia. About 40 U.S. troops from the 101st Airborne Division arrived in Mogadishu, Somalia on April 2, Voice of America’s Carla Babb reported Thursday. “The troops' arrival marks the first presence of American military forces in Somalia, other than a small unit of counterterrorism advisers, since March 1994.”

Reminder: As many as 300 U.S. special operators are already in country, as The New York Times reported back in October. The headline there: “In Somalia, U.S. Escalates a Shadow War” against fighters from the al-Qaeda-linked al-Shabab group.

Writes VOA: The conventional troops are “carrying out a train-and-equip mission that is expected to last through the end of September...The move is another example of the acceleration of U.S. efforts to help combat violent extremism across the globe, a second military official said. The goal of the operation is to build partner capacity while helping to improve the logistics of local forces battling the military group al-Shabab.” Read the rest, here.

More U.S. troops for Syria? The White House is working that one out… National Security Adviser Lt. Gen. H.R. McMaster votes yes; his boss—the president—says no, according to Bloomberg View’s Eli Lake.

Part of the problem: former NSA Mike Flynn opposed more troops in Syria. McMaster’s “supporters insist he is only trying to facilitate a better interagency process to develop Trump's new strategy to defeat the self-described caliphate that controls territory in Iraq and Syria.”

Another complicating factor: “The White House and administration officials say Secretary of Defense James Mattis, Chairman of the Joint Chiefs of Staff Joseph Dunford and General Joseph Votel, who is in charge of U.S. Central Command, oppose sending more conventional forces into Syria.”
Making matters more complicated: “White House senior strategist Stephen Bannon has derided McMaster to his colleagues as trying to start a new Iraq War, according to these sources.” Much more to the story, here.

The shot heard round the world. 11 tons of TNT is "the right munition" for "IEDs, bunkers and tunnels," Afghan war commander Gen. John “Mick” Nicholson said of the GBU-43 Massive Ordnance Air Blast (MOAB) bomb that the U.S. Air Force Special Operations pilots dropped on an alleged Islamic State affiliate’s position in the eastern Nangarhar province of Afghanistan, bordering Pakistan, on Thursday.

Said Nicholson this morning: "It was the right time to use it tactically against the right target on the battlefield” and the weapon “achieved its intended purpose."

Watch the explosion consume most of the screen in this grainy, gray surveillance footage shared by CENTCOM.

The battle damage assessment: “As many as 36 suspected Islamic State militants were killed in the strike on Thursday evening, Afghan defense officials said, adding there were no civilian casualties,” Reuters reports this morning.

For what it’s worth: “U.S. military officials estimate there are about 600 to 800 Islamic State fighters in Afghanistan, mostly in Nangarhar, but also in the neighboring province of Kunar,” Reuters adds.

Not a fan of the strike: former Afghan President Hamid Karzai. "This is not the war on terror, but the inhuman and most brutal misuse of our country as testing ground for new and dangerous weapons," he said on Twitter Thursday.

A bit more on the bomb itself: The MOAB uses grid fin guidance technology that the U.S. stole from the Soviets, Defense One’s Marcus Weisgerber reported back in August.  

Its explosive yield is 0.011 kilotons, whereas the typical nuclear yield is 10 to 180 kilotons, said former SecDef William Perry, who adds, “The U.S. alone possesses over 7000 nuclear weapons.”

“The big bomb will get more play than the big oops, even if the latter is more strategically significant,” said one observer on Twitter. That “big oops”—the coalition airstrike that killed a dozen-and-a-half Syrian Democratic Forces fighters south of Tabqa on Tuesday.

Added the airstrike monitors at AirWars: “Donald Trump's promise to ‘bomb the shit out of ISIS’ is coming true. Munitions dropped in first 3 months of 2017 is up 59 percent over 2016.”

What’s more, a “huge rise in civilian deaths from Coalition actions in Syria during March was not due to more strikes or targets hit (both were down).” More to their analysis, here.

What’s it like to evade an ISIS armed drone? The New York Times’ Ben Solomon was on the front lines in Mosul, Iraq, when one of those drones approached from above. Watch his video report from the scene, here.

Today in things not to do on the battlefield: Toss an RPG to your comrade over a small wadi west of Mosul, Iraq. The culprits: Iranian-aligned Popular Mobilization Units, which have been fighting the stalwart ISIS presence near Tal Afar for months. Photo, here.

In more useful ways to fight ISIS, here’s a deep-dive into how to stop the group’s suicide car bomb fleet. The “required weaponry” includes heavy machine guns like the M2 Browning or the DshK; anti-tank guided missiles (ATGMs) like the FGM-148 Javelin, the Milan, or Chinese HJ-8s mounted on Humvees; tank guns like 100 mm D-10, 120 mm M256 or 125 mm 2A46; and use of trenches and earth berms to shake up the vehicles to prompt an early trigger before it hits its target. All that and much more, here.

Seven allied spy agencies all found Trump campaign team contacts with Russia, The Guardian reported Thursday. Those nations: UK, Germany, Estonia, Poland, Australia, France, and the Netherlands. “It is understood that GCHQ was at no point carrying out a targeted operation against Trump or his team or proactively seeking information. The alleged conversations were picked up by chance as part of routine surveillance of Russian intelligence assets. Over several months, different agencies targeting the same people began to see a pattern of connections that were flagged to intelligence officials in the US.” Story—it’s a long one—here.

Who’s the latest to have such contacts revealed? It’s Jared Kushner, Trump son-in-law and senior adviser, who omitted several contacts with Russian officials on his application for a security clearance. Now Congressional Democrats want that clearance revoked. Politico, here

And lastly this week: GCHQ has put out a “final call” for Russian linguists. The pitch: “We are looking for linguists for roles that will go well beyond translation and transcription. It takes knowledge of the culture, history, politics and ideology to fully understand the original idea. And if you can do that, you can enable MI5 and GCHQ to make the right choices to help safeguard national security.” Details, here. Have a safe Easter weekend, gang. And we’ll see everyone again on Monday.