DAMASCUS, Syria -- Russia's deputy foreign minister on Saturday called on the United States and Europe to take "serious" steps to combat terrorism, warning that several Middle Eastern countries are threatened.

"Russia will not stand idle toward attempts by terrorist groups to spread terrorism in regional states," Sergei Ryabkov told reporters during a visit to Damascus, apparently referring to the rapid advance of the extremist Islamic State of Iraq and the Levant across eastern Syria and northern Iraq.

Russia has been one of Syrian President Bashar Assad's main allies since the start of an uprising against him in March 2011. Moscow has used its veto power four times at the UN Security Council to prevent international sanctions on Syria.

Both Russia and Assad's government have portrayed the civil war in Syria as a struggle against foreign-backed "terrorists," the word Damascus applies to all rebels fighting to end the Assad family's four-decade reign.

"There must be a confrontation of terrorism by taking integral measures against radicalism and by searching for a solution to prevent the influx of fighters from abroad," Ryabkov said, adding that terrorism will have "catastrophic repercussions" on the entire region.

Thousands of foreign fighters, including hundreds from the former Soviet Union, are fighting against Assad's forces in different parts of Syria, mainly on behalf of the Islamic State, which has carved out a sprawling enclave astride the Syrian-Iraqi border.

Ryabkov praised Damascus' "responsible" decision to give up its chemical weapons, saying that doing so has boosted Syria's security.

On Monday, Syria finished handing over to Western powers 1,300 tons of chemical weapons it acknowledged possessing, completing a deal reached last fall under threat of U.S. airstrikes.

Ryabkov held talks a day earlier with Syrian Foreign Minister Walid al-Moallem and his deputy, Faisal Mekdad.

According to the state-run Syrian Arab News Agency, Ryabkov congratulated al-Moallem on removing "all chemical material" from the country.