PARIS — Russia said late Thursday that the Syrian military has suspended its combat operations in eastern Aleppo to allow civilians to leave the city and that it had reached agreement with the United States to negotiate the safe departure of rebel fighters.

A senior U.S. State Department official here traveling with Secretary of State John F. Kerry said that neither of those assertions could yet be confirmed but that Kerry was in contact with Russian Foreign Minister Sergei Lavrov.

There were conflicting reports from inside Aleppo, where some residents reported a sudden quiet, but others said neighborhoods were still under fire. On Wednesday, as many as 150 elderly residents of Aleppo’s Old City were evacuated by the government in a joint operation with the International Red Cross.

Lavrov, speaking to Russian journalists in Hamburg, said a much bigger evacuation was underway. “Yet another and the biggest [operation] so far . . . to evacuate the civilians willing to leave the place is underway there,” he said, according to Russia’s state-owned Tass news agency. “There are some 8,000 people in the column. That’s a huge operation, and the withdrawal route is five kilometers long.”