The Russian military said Wednesday it's ready to resume contacts with its U.S. counterparts over the situation in Syria, even as U.S. Secretary of State John Kerry threatened to cut all cooperation with Moscow on Syria unless an onslaught on Aleppo ends.

Lt. Gen. Viktor Poznikhir of the military's General Staff said Wednesday that Russian experts are ready to travel to Geneva to restart consultations with the U.S. to "search for possible ways of normalizing the situation in Aleppo."

A U.S.-Russian truce in Syria has collapsed and the Syrian government forces backed by Russian warplanes have launched an attempt to take control of the rebel-held neighborhoods of Aleppo.

Kerry said Wednesday the U.S. is preparing to "suspend U.S.-Russia bilateral engagement on Syria," including talks on a possible counter-extremist partnership, 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.

Poznikhir didn't make any reference to Kerry's statement, saying only that Russia was ready to continue discussions.

"It's expected that Russian experts will be sent to Geneva shortly to resume consultations with the American side," he said. "We hope that American partners are also ready for joint work."

The U.S.-Russian deal brokered Sept. 9 envisaged cooperation between the two militaries against the Islamic State group and al-Qaida's branch in Syria if the declared cease-fire held, but it collapsed amid renewed fighting and mutual acrimony. The U.S. blamed Russia for an attack on a humanitarian convoy outside Aleppo, accusations Moscow has denied.

Poznikhir said the Russian military got new information about Syrian rebels' involvement in the attack on the convoy, but he didn't offer any details.

Like other Russian officials before him, he has blamed the rebels for the collapse of the truce, adding that an increasing number of Syrian opposition units have integrated with al-Qaida's affiliate in Syria. He also alleged that the militants are preparing to strike sections of Aleppo with chemical weapons to heap the blame on the government.

"It has become known to us that terrorist groups are preparing to strike Syrian army positions and residential quarters in the eastern part of Aleppo with projectiles loaded with toxic agents as a provocation, in order to put the blame on the government forces," he said.