Secretary of State John F. Kerry. (David Mdzinarishvili/Associated Press)

While the United States and Russia inch closer to more military cooperation in Syria on the ground, Secretary of State John F. Kerry is sounding more and more like he agrees with the Russian view of the Syrian rebel groups fighting against the Assad regime.

Late last month in Aspen, Colo., Kerry said the most important thing the administration is doing to ramp up the effort to defeat extremists in Syria is to “reach an understanding” with the Russian government about how to deal with the terrorists there, which he names as the Islamic State, often referred to as Daesh, and Jabhat al-Nusra, al-Qaeda’s Syrian branch. As I reported, Kerry and President Obama have proposed to Moscow increased cooperation against those groups, especially Jabhat al-Nusra, in exchange for Russia convincing Syrian President Bashar al-Assad to abide by the crumbling cease-fire and lay off bombing the other rebels.

But then Kerry, perhaps accidentally, threw two other Syrian rebel groups under the bus by calling them “subgroups” of the terrorists.

“There are a couple of subgroups underneath the two designated — Daesh and Jabhat al-Nusra — Jaysh al-Islam, Ahrar al-Sham particularly — who brush off and fight with that — alongside these other two sometimes to fight the Assad regime,” he said, referring to two rebel groups that the United States has not named as terrorist groups until now.

The remark, which went largely unnoticed by the media in Aspen, nonetheless set off alarm bells inside the Obama administration. Two administration officials who work on Syria told me that Kerry’s naming of the Jaysh al-Islam and Ahrar al-Sham as “subgroups” of the terrorist organizations was not only inaccurate but potentially harmful to U.S. government efforts to convince the Russians and the Syrian government not to attack them.

“For months, we’ve been arguing to make sure the Russians and the Syrian regime don’t equate these groups with the terrorists,” one senior administration official told me. “Kerry’s line yields that point.”

Another U.S. official simply emailed, “Baffled. SMH[Shaking my head].”

State Department spokesman John Kirby told me that there has been “absolutely no change” in the U.S. government’s support for the policy that only groups designated by the United Nations as terrorists groups should be excluded from the cease-fire, also known as the “cessation of hostilities.”

“Secretary Kerry was simply trying to describe the complexity of the situation in Syria, noting that we aren’t blind to the notion that some fighters shift their loyalties,” he said.

Even if Kerry misspoke, some Syrian groups see his comments as an example of how the Obama administration has slowly but steadily moved toward the Russian view of Syria, which includes painting all opposition groups as terrorists.

“Russia considers all revolutionaries and rebel groups as ISIS or al-Nusra to justify its indiscriminate shelling of civilians and the moderate opposition,” said Mouaz Moustafa, executive director of the Syrian Emergency Task Force, an American nongovernmental organization that works with Syrian rebel groups.

Ahrar al-Sham is made up of Islamic and Salafist units and does not believe in a secular, democratic Syria, but it is not an al-Qaeda subsidiary and doesn’t take direction from Jabhat al-Nusra, Moustafa said. Jaysh al-Islam is supported by U.S. allies including Saudi Arabia and has been part of the opposition negotiating team in the Geneva process.

Russia’s obligation, under the new proposed cooperation deal, is to stop bombing Syrian rebel groups the U.S. declares are not terrorists. It’s true that the groups fighting Assad are hard to distinguish and often co-mingle, but U.S. policy is based on knowing which are which. Kerry muddied the waters. That’s typically Moscow’s job.