Amid reports that Syrian peace talks are at an impasse, U.S. President Barack Obama urged his Russian counterpart Vladimir Putin to use his influence with the Assad regime during a phone call early Monday.
White House Press Secretary Josh Earnest confirmed Obama had an "intense" conversation with Putin that centered on the situation in Syria and concern about all of the parties living up to commitments made in the cessation of hostilities.
"President Putin has publicly expressed his view that this kind of political transition is critical to both Russian and U.S. interests in [Syria] and in the broader region, and this is an opportunity where our interests overlap," Earnest told reporters.
In a readout of the call, the White House said Obama "stressed the importance of pressing the Syrian regime to halt its offensive attacks against the opposition."
In its statement on the call, the Kremlin said Putin "stressed the need for the moderate opposition to distance themselves swiftly from ISIS and [al-Qaida affiliate] Jabhat al-Nusra, and to close Syria's border with Turkey, from where fighters and arms supplies for the extremists make their way in."
ISIS is an acronym for the Islamic State.
During Monday's briefing, Earnest said the "fragile" and "increasingly threatened" cessation of hostilities was critical to a successful political transition in Syria.
The two presidents also spoke on Ukraine, with Obama calling on Putin to "take steps to end the significant uptick in fighting in eastern Ukraine" and implement the Minsk agreement.
"President Obama continues to make a forceful case that Russia needs to abide by their commitments, and by doing so they can begin to relieve some of the isolation that they have sustained as a result of interfering in the sovereign activities of their neighbors in Ukraine," the White House press secretary said.
For its part, the Kremlin said Putin expressed "hope that with the new Ukrainian government in place now, the authorities in Kyiv will finally start taking concrete steps toward implementing the Minsk agreements."
An issue that was not addressed in Monday's call was the recent incident in the Baltic Sea where the U.S. military says Russian jets flew within 30 feet (10 meters) of the U.S. Navy destroyer the USS Donald Cook.
More recently, the U.S. military says a Russian jet "barrel-rolled" a U.S. Air Force reconnaissance flight last week. Russia disputes the account.
Earnest said the incidents were not elevated beyond the U.S. military attaché in Moscow expressing U.S. concerns to his Russian counterpart.
"Those kinds of activities are destabilizing and a source of some concern, but they are not particularly unusual," Earnest noted.