Russian President Vladimir Putin slammed the U.S. stance on the Syrian conflict as "unconstructive," after Washington declined to take part in high-level, bilateral negotiations on coordinating military activity in Syria, as Syrian forces, supported by Russian jets, launched an attack on rebel-held towns north of the city of Homs Thursday.
Putin's comments came a day after the U.S. and Russia wrapped up a third round of lower-level talks on rules for conduct in the air over Syria, where both countries are conducting separate airstrike campaigns.
Both the U.S. and Russia said progress was made during the video conference talks Wednesday, which Washington said were "focused narrowly on the implementation of specific safety procedures."
On Wednesday, Moscow said Washington refused its offer to discuss further military cooperation in the war-torn country. The U.S. has strongly criticized Russia's military campaign in Syria.
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In comments published Thursday by the Interfax news agency, Putin said he does not understand how U.S. officials can criticize the Russian military operations "if they refuse to conduct the direct dialogue on this very important track.
"I believe that this stance is unconstructive," Putin added.
A U.S. State Department spokesman Wednesday said he did "not have anything specific" on the proposal for higher-level talks. John Kirby also said the U.S. continues to show a willingness to talk with Russian authorities.
U.N. envoy for Syria Staffan de Mistura is pushing a separate effort to get the U.S. and Russia on the same page in working toward a broad political resolution to the crisis in Syria.
Russia on Thursday carried out airstrikes to provide cover for an offensive by Syrian government troops in the central province of Homs, according to Syrian state television and activists.
State television said Syrian troops captured the town of Khaldiyeh near the main city of Hama and killed several militants near the city of Homs.
Russian warplanes launched at least 15 airstrikes on the rebel-controlled town of Talbisseh, killing at least 10 people, six of whom were rebels, according to the Britain-based Syrian Observatory for Human Rights.
Gains by Islamic State fighters north of Aleppo would threaten the supply lines of rival rebels inside the city, which is divided between insurgents and government forces.
Separately, Russia's Defense Ministry said one of its fighter jets approached a U.S. warplane in Syrian airspace last week only for identification purposes. Spokesman Igor Konashenkov said the Russian jet came within two to three kilometers of the U.S. plane in Aleppo province on a mission that was not intended to scare or provoke anyone. He said the Russian jet then returned to its fighting group.
Russian airstrikes have helped Syrian government troops regain territory, while the U.S. has criticized its campaign as targeting mostly rebel fighters and not Islamic State militants.