The White House on Tuesday said Russia so far appears to be fulfilling a decision to withdraw troops from Syria, but cautioned it was too soon to judge the impact, AFP reports.

"The earliest indications are that the Russians are following through," said White House spokesman Josh Earnest, as the first of Russia's warplanes to leave Syria received a hero's welcome back home.

The Pentagon reported it had seen "some Russian aircraft depart Syria and return to Russia" although that did not amount to "a large contingent of Russian forces."