ISIS advance in NW Syria; Surprise, surprise—USSOF are in Syria; The Shi’a side of the Fallujah offensive; Captured IS fighters are snitching on Baghdadi; Memorial Day and the National Parks; And a bit more.

ISIS has reportedly made its biggest advance in two years in the Syrian governorate of Aleppo, bringing Islamic State fighters “to within 5 km (3 miles) of Azaz, a town near the border with Turkey through which insurgents have been supplied,” Reuters reports this morning.

Newsflash: American special forces are in Syria, and Agence France-Presse has photographic evidence they’re fairly invested in the fight—maybe not positioning themselves at the precise front of the Syrian Democratic Forces’ advancing on ISIS in Raqqa governorate… but they’re pretty darn close.

Pentagon reax: “They’re not on the forward line” of troops, Press Secretary Peter Cook told reporters Thursday afternoon, just hours after the photos began circulating. But, as The Hill’s Kristina Wong reports, Cook acknowledged there was no ‘specific measurement’ for what the ‘forward line’ is.”

What’s more complicating is the AFP report included quotes from a Syrian rebel commander saying American troops were “present at all positions along the front. ... They are taking part on the ground and in the air.”

But as far as distance to ISIS HQ—The Daily Beast says the American troops are a mere 18 miles from Raqqa city.

For the record: Those SDF troops are composed of 5,000 Arab fighters and 25,000 Kurds, AFP writes.

But it was the yellow YPG patches the U.S. special forces wore on their shoulders that has Turkey throwing fits this morning, AP reports from Ankara: “Foreign Minister Mevlut Cavusoglu said during an international conference in southern Turkey that it was ‘unacceptable’ for soldiers of a Turkish ally to use the patches of the YPG — the Kurdish People's Protection Units which are fighting the Islamic State group in northern Syria. He said Turkey had relayed its displeasure to U.S. officials in Washington and in Turkey, and rejected explanations that the patches were for the soldier's protection,” as Cook suggested Thursday.

Captured ISIS fighters are reportedly singing like canaries about leader Abu Bakr al-Baghdadi, The Guardian’s Martin Chulov and Spencer Ackerman report. Kurdish and Western intelligence officials have been piecing together information that suggests Baghdadi stayed stationary for about six months after being critically wounded in an airstrike about 190 miles north of Baghdad. Where did he hide? Reportedly in a corner of Iraq, near Ba’ej and Tal Afar. Then he began traveling semi-regularly.

“Details of Baghdadi’s injuries have been shared across the Five Eyes intelligence community of the US, UK, Australia, Canada and New Zealand, and among partners in the Middle East, including the Kurds, Iraq, Saudi Arabia and the Gulf States,” Chulov and Ackerman write. “However, a divide remains between intelligence officers who wanted to disclose the details and policy makers who chose not to. The discussion centred on who would end up prevailing in the court of public opinion if information about a failed and accidental attack was revealed.” Lots more to sink your teeth into, here.

In Iraq, the Fallujah offensive is about to crank up a notch, a Shiite commander told Reuters. “The first phase of the offensive that started on Monday is nearly finished, with the complete encirclement of the city that lies 50 km (32 miles) west of the capital, said Hadi al-Amiri, the leader of the Iranian-backed Badr Organization. Amiri, in military fatigues, spoke to state-TV from the operations area with Prime Minister Haider al-Abadi standing by his side, wearing the black uniform of Iraq's counter-terrorism force.”

Amiri had also said this week that “the Shi'ite paramilitary coalition known as Popular Mobilization will only take part in the encirclement operations, and would let the army storm Falluja,” Reuters writes. “Popular Mobilization would only go in the city if the army's attack fails, he said.”

Baghdad’s troops are trying to fight a war around 50,000 civilians in Fallujah, The Atlantic’s Marina Koren reports after a dire warning on starvation among civilians in the city, which came from UN earlier this week.

ICYMI: AQ is still reaping windfall oil profits in Yemen, Reuters also reports in a follow-up to their April investigation into the group’s financing in the Middle East’s other war-torn country.

From Defense One

Ash Carter wants American military engineers to give “surprising new capabilities to old platforms,” he told at the Naval Undersea Warfare Center at Middleton, Rhode Island, on Thursday. Defense One’s Bradley Peniston traveled with Carter as he showed a geek’s love for new technology—and a layered concept of what “innovation” means to the Pentagon. That, here.

Don’t give up on the African Union mission yet; it’s the only force that can counter al-Shabab and hold territory, argues Alex Dick-Godfrey of the Council on Foreign Relations, writing in Defense One.

Welcome to Friday’s edition of The D Brief, by Ben Watson and Marcus Weisgerber. On this day in 1999, the International War Crimes Tribunal announced an indictment against Serbian President Slobodan Milošević for war crimes from a conflict that appalled many in the U.S. military and the international community over how long it took to eventually bring an end to the worst fighting in the Bosnian War. Send your friends this link: And let us know your news:

Obama goes to Hiroshima to call for a nuke-free world. "Amongst those nations like my own that own nuclear stockpiles, we must have the courage to escape the logic of fear and pursue a world without them," he said in what the AP calls “a carefully choreographed display” which saw the president offer “a somber reflection on the horrors of war and the danger of technology that gives humans the ‘capacity for unmatched destruction.’”

Said Obama: “Death fell from the sky and the world was changed… The flash of light and a wall of fire destroyed a city and demonstrated that mankind possessed the means to destroy itself.”

Added his Japanese counterpart, Prime Minister Shinzo Abe: “At any place in world, this tragedy must not be repeated again.”

Reuters reminds us: “Obama's main goal in Hiroshima was to showcase his nuclear disarmament agenda, for which he won the 2009 Nobel Peace Prize.”

Perhaps he read Joe Cirincione’s piece, here, that reminds us of the incomprehensible power of the U.S. nuclear arsenal contained in that briefcase carried by an aide everywhere POTUS goes.

U.S. tightens air strike rules after Kunduz. From “The lessons learned from the airstrike on the Doctors Without Borders hospital in Afghanistan have reverberated through U.S. Central Command and led pilots to pay even closer attention to the already strict rules of engagement, the top general for the Iraq-Syria air war said Thursday. The bottom line was that ‘if you have any doubt, don't drop’ to avoid civilian casualties, Air Force Lt. Gen. Charles Q. Brown Jr., commander of U.S. Air Forces Central Command, said in a video briefing from the Mideast to the Pentagon.” More here.

Goodbye tour begins for Gen. Mark Welsh. And the U.S. Air Force chief of staff, who is retiring at the end of next month, was direct in his comments to an audience largely made up if defense industry executives. Here are the highlights:

How much has the Air Force shrunk? If there was a major war, almost 100 percent of the Air Force would be deployed, Welsh said. Even without a major war, the service needs 40,000 to 60,000 more people to do its job, Welsh said. Would more money help? Not with manpower issues, Welsh said. They simply need more people. While on the subject of money: “If you want to continue to use your military as if you are the global superpower, then it's going to require investment,” he said. More from Air Force Magazine here and here.

It’s difficult to cut generals. Welsh said his efforts to make reductions to the Air Force’s senior general officer ranks oftentimes came up short. Specifically, he tried to cut 15 three-star billets and two four-star billets. In the end, only eight three-start cuts were approved.

What’s the right size for the B-21 stealth bomber fleet? Let’s not worry about that now, Welsh said. He’d rather focus on getting the project up and running well and then determining the proper size. The Air Force has said it wants to buy between 80 and 100 new bombers.

Laser firing Apaches. U.S. Special Operations Command wants ‘em. SOCOM will test an Apache attack helicopter with a laser weapon this summer, National Defense Magazine reports. “There is absolutely a niche I believe for use of directed energy weapons,” Col. John Vannoy, program manager for rotary wing, said at the Special Operations Forces Industry Conference sponsored by the National Defense Industrial Association. “The lens we are looking at this through right now is: ‘Is it feasible to do this?’ We’re not at the point where we’ve laid out a business case to advance it.” More here.

Navy facing an $848 million operations and maintenance shortfall. Citing a service official, Defense News reports that “while there will be no impact to forces already deployed, continuing problems ‘would likely delay some deployments.’” More here.

Heads up, gang: No D Brief on Monday in observance of the Memorial Day holiday. We’ll be back on Tuesday morning. In the meantime, here are 15 ways to observe Memorial Day in national parks courtesy of the National Parks Foundation.  Be safe out there.