WASHINGTON — Secretary of State John Kerry threatened on Wednesday to end all cooperation between the United States and Russia to stop Syria's civil war, unless Russian and Syrian government attacks on Aleppo end. More than 250 people are believed to have been killed in the besieged city in the last week.
Kerry's warning came in a telephone call Wednesday to Russian Foreign Minister Sergey Lavrov, the State Department said, describing the latest U.S. ultimatum in Syria's 5½-year conflict. Many have gone unfulfilled, including President Barack Obama's declaration that the U.S. would take military action if Syrian President Bashar Assad crossed the "red line" of using chemical weapons.
It was unclear what effect Kerry's words would have.
"The burden remains on Russia to stop this assault and allow humanitarian access to Aleppo and other areas in need," Kerry told Lavrov, according to State Department spokesman John Kirby.
Kerry said the U.S. is preparing to "suspend U.S.-Russia bilateral engagement on Syria," including talks on a possible counter-extremist partnership, "unless Russia takes immediate steps to end the assault on Aleppo and restore" a cease-fire.
Government shelling and airstrikes landed near a bread distribution center and two hospitals in Aleppo on Wednesday. Activists and medics reported several people killed. They said at least one of the medical facilities was no longer operable, leaving the country's biggest city with only six functioning hospitals.
The Syrian government and its ally Russia have been accused of intentionally targeting medical facilities in rebel-held areas. The U.S.-based Physicians for Human Rights has recorded 382 such attacks throughout Syria since the conflict started in 2011. The group says government forces carried out 293 of the attacks; Russian warplanes conducted 16.
Despite Moscow's military engagement in the war alongside Assad's government, Washington has been working with its former Cold War foe in hopes of securing a cease-fire and a peace process. The latest effort collapsed last week after several days of reduced violence, but the U.S. and Russia have been discussing ways to revive it.
The Obama administration had hoped the promise of the new U.S.-Russian alliance against the Islamic State group and al-Qaida affiliates would be enough to get Moscow to ground Assad's forces.
Current coordination to ensure U.S. and Russian planes stay out of each other's way will continue no matter what, the Pentagon said. The U.S. and its coalition partners are flying missions in Syria against IS; the U.S. also has a small contingent of special forces on the ground.
Kerry's threat aside, the U.S. has few other options beyond engaging Moscow to end the fighting between Assad's forces and rebels.
Obama has made clear he won't authorize military action against Syria and the presence of Russian air assets alongside Syrian forces makes such a scenario all the more unlikely. The U.S. is similarly uncomfortable ramping up military support for anti-Assad rebels given the close ties even the so-called "moderate" groups maintain with al-Qaida-linked militants.
Peace efforts without Russia are unlikely to win over Assad. And green-lighting Saudi Arabia, Qatar, Turkey or other countries to provide more weapons to the rebels could only make the war deadlier. Already, as many as 500,000 people have been killed.
In the telephone call with Lavrov, Kerry "expressed grave concern over the deteriorating situation in Syria, particularly for continued Russian and Syrian regime attacks on hospitals, the water supply network and other civilian infrastructure in Aleppo," Kirby's statement said.
"The secretary made clear the United States and its partners hold Russia responsible for this situation, including the use of incendiary and bunker buster bombs in an urban environment, a drastic escalation that puts civilians at great risk."
Russia's Foreign Ministry presented a different version of the call, making no reference to the U.S. ultimatum.
It focused on Lavrov's demand that the U.S. compel opposition forces to separate themselves from extremist groups. He told Kerry that many U.S.-backed groups have merged with the al-Qaida-linked Nusra Front and said Nusra was getting U.S. weaponry that way.
Nevertheless, Lavrov and Kerry discussed ways to "normalize" the situation in Aleppo and "return to the basic principles" of the Sept. 9 cease-fire, the ministry said.
Associated Press writer Vladimir Isachenkov in Moscow contributed to this report.