Most if not all Russian warplanes have been withdrawn from Syria, a spokesman for the United States military said Friday, adding that Russia has staged no air strikes during the past week.

However, the American military assessment contradicted assertions by the Russian military that its jets were flying as many as 25 sorties a day in support of a Syrian government offensive to recapture the ancient city of Palmyra from Islamic State (ISIS) group fighters.

U.S. Central Command spokesman Colonel Patrick Ryder said some bombardments have taken place in the Palmyra region but that they were believed to have been fired by Russian artillery.

“In the last week, we have not seen any Russian aircraft conducting any strikes in Syria,” Ryder said in a telephone briefing with reporters.

Russian President Vladimir Putin on Monday unexpectedly announced a partial withdrawal of Russian forces from Syria, where they have been backing Moscow’s close ally Syrian President Bashar Al-Assad.

The first Russian aircraft returned Tuesday to a hero’s welcome. The Syrian rebels declared a “victory” after the Russian withdrawal from Syria.

“We assessed that the majority if not all of their strike aircraft have left,” Ryder said Friday of the Russian withdrawal.

The United States military, which was taken by surprise by the development, has remained skeptical of Putin’s intentions.

On Thursday, a Baghdad-based American military spokesman, Colonel Steve Warren, said there had been little change in Russian troop deployments on the ground.

There has been little movement of Russian ground forces, Ryder said, adding that Moscow has kept combat helicopters and some transport planes in Syria.

Russia intervened militarily in the Syrian civil war on September 30 at Assad’s request, deploying about 50 combat aircraft.

It also sent more than 4,000 ground troops, artillery, tanks and about 30 combat helicopters.

The Russians have directed their operations mainly against Western-backed anti-government rebels while an international led coalition has been waging an air campaign against ISIS.

AFP contributed to this report.

(Arutz Sheva’s North American desk is keeping you updated until the start of Shabbat in New York. The time posted automatically on all Arutz Sheva articles, however, is Israeli time.)