Russian President Vladimir Putin ordered a partial withdrawal of Russian troops from Syria during a visit to the war-torn country on Monday.
Putin was met at Russia's Hmeimim air base by Syrian President Bashar al-Assad alongside Russian Defense Minister Sergei Shoigu, according to Russian state news agency Tass.
"In two years, the Russian armed forces, together with the Syrian army, have defeated the most lethal group of international terrorists," Tass quoted Putin as saying.
"In this regard, I have decided that a significant part of the Russian military contingent in the Syrian Arab Republic is returning home to Russia."
Putin's visit to Syria comes just weeks after the two Presidents met for talks in the Russian city of Sochi. Putin has been one of the chief supporters of Assad's government, and Russia's intervention in the country's long-running civil war in 2015 helped tilt the balance of power back in Assad's favor.
This is not the first time Putin has declared his intention to withdraw troops from Syria. Putin said two Russian bases in the country, Hmeimim and Tartus, would continue to operate despite the drawdown.
"If terrorists will raise their heads ever again, we will strike them with such force that they have never seen before," Putin said in remarks Monday that were broadcast on the state-owned Russia 24 new channel.
Putin then flew on to Cairo for talks with Egyptian President Abdel Fattah el-Sisi, and was expected to meet Turkish President Recep Tayyip Erdogan in Ankara later on Monday.
Putin's Syria visit comes two days after the Iraqi military said in a statement that it had "fully liberated" all of Iraq's territory of "ISIS terrorist gangs" and retaken full control of the Iraqi-Syrian border.
"We defeated Daesh (ISIS) through our unity and sacrifice for the nation. Long live Iraq and its people," Iraqi Prime Minister Haider Al-Abadi wrote on Twitter.
ISIS captured huge chunks of territory in Iraq and Syria in 2014 and announced the creation of a caliphate on those lands. At the height of its power, the group controlled more than 34,000 square miles of territory from the Mediterranean coast to south of Baghdad.
The campaign to eradicate ISIS has taken more than three years and about 25,000 coalition airstrikes. The group was pushed out of Mosul and Raqqa, its de facto capitals in Iraq and Syria, this year, and has since lost almost all of the areas it once controlled.