MOSCOW (Reuters) - Russian President Vladimir Putin has congratulated Syrian President Bashar al-Assad on regaining the city of Palmyra, the Kremlin spokesman said on Sunday.

Russian President Vladimir Putin (R) shakes hands with Syrian President Bashar al-Assad during a meeting at the Kremlin in Moscow, Russia, in this October 20, 2015 file photo. REUTERS/Alexei Druzhinin/RIA Novosti/Kremlin/ Files

“Assad highly valued the help Russian air forces have provided and underlined that such successes as regaining Palmyra would have been impossible without Russia’s support,” Dmitry Peskov said, quoted by TASS news agency.

Syrian government forces backed by heavy Russian air support drove Islamic State out of Palmyra on Sunday, inflicting what the army called a “mortal blow” to militants who seized the city last year and dynamited its ancient temples.

The loss of Palmyra represents one of the biggest setbacks for the hardline Islamist group since it declared a caliphate in 2014 across large parts of Syria and Iraq.

Peskov said that Putin told Assad that Russia will continue to support Damascus in fighting terrorists, TASS reported. Putin also talked to UNESCO head Irina Bokova on Sunday, saying that Russia will help to demine Palmyra, Peskov added.

Syrian television said Assad told Putin that Russian air support and the determination of Syria’s armed forces were key to the success in Palmyra.

He also said the city would be rebuilt.

“Palmyra was demolished more than once through the centuries...and we will restore it anew so it will be a treasure of cultural heritage for the world,” it quoted him as saying.

Earlier in March, Putin ordered the bulk of the Russian military contingent in Syria to be pulled out after five months of air strikes, saying the Kremlin had achieved most of its objectives.

But Putin said later that Russia could scale up its military presence in Syria again within hours and would still bomb terrorist groups there despite a partial withdrawal of forces ordered after military successes.