Russian President Vladimir Putin pledged to continue providing military aid and intelligence to Syrian President Bashar al-Assad, declaring that Russian warplanes could redeploy to Syria at any moment.

“If it is needed, Russia is capable of boosting its numbers of its presence in Syria literally in a few hours, depending on the situation, and use the full power of our capabilities,” Mr. Putin said on Thursday in an address to Russian military personnel who served in Syria.

On Monday, Mr. Putin said the bulk of Russian military forces would withdraw from Syria, after a bombing campaign that began at the end of September—a nearly six-month mission the Russian president said had cost some 33 billion rubles ($477.5 million). Russia’s announcement surprised U.S. and Western officials, and raised questions about the direction of nascent peace talks that began in Geneva the same day.

Mr. Putin said the Syrian president was ready for compromise. The move to withdraw Russian warplanes, he added, was an important step given the talks in Geneva.

Russian officials have said they plan to retain an airbase outside the port city of Latakia, and a naval station in Tartus. Mr. Putin said Russia’s military bases in Syria would be protected by advanced air defenses.