Russia's President Vladimir Putin announced in a surprise move this week that he would begin pulling troops out of Syria, saying his mission in the country had been accomplished.
Putin, who has long been an ally to Syrian President Bashar al-Assad, announced his decision Monday while meeting with members of his cabinet at the Kremlin.
The Russian leader indicated that he would begin pulling out the "main part" of his forces on Tuesday, saying that his country's mission in Syria had been largely successful and did not need to continue.
"I consider the mission set for the defense ministry and the armed forces on the whole has been accomplished," Putin said, adding that the decision was made "in accordance with the situation on the ground [in Syria]."
"I am therefore ordering the defense ministry to begin the withdrawal of the main part of our military force from the Syrian Arab Republic from tomorrow," Putin added.
While several Russian aircraft departed Hmeimim air base on Tuesday, Putin indicated that the country will continue with its airstrikes and still keep some personnel on the ground.
As BBC News reports, Russia's involvement in the Syrian conflict began last September, and was seen as a boon to Syrian President Bashar al-Assad's fight against opposition groups.
While some media outlets suggest that there has been a disagreement between Putin and al-Assad leading to Russia's sudden exit, the countries have maintained that the decision was mutual.
"The whole subject happened in complete coordination between the Russian and Syrian sides, and is a step that was carefully and accurately studied for some time," the Syrian presidency said in a statement.
The White House released a statement this week indicating that Putin and President Obama had discussed the Syria situation via phone, although it was unclear if the U.S. had prior knowledge of Russia's plan to leave.
The statement indicated that the two world leaders discussed the "next steps required to fully implement the cessation of hostilities with the goal of advancing the political negotiations on resolution of the conflict."
"President Obama welcomed the much-needed reduction in violence since the beginning of the cessation, but stressed that continuing offensive actions by Syrian regime forces risk undermining both the Cessation of Hostilities and the UN-led political process," the statement added.
According to the Wall Street Journal, Russia's sudden departure from Syria may put more pressure on al-Assad to negotiate in peace talks that began with the United Nations this week. The talks are aimed at ending the years-long war in Syria.
Staffan de Mistura, the special U.N. representative overseeing the talks, said in a statement on Monday that the first meeting with Syria had been "useful" and laid the ground work for productive subsequent meetings.
"It was a useful meeting, and I think we clarified quite a lot of the issues," de Mistura said, adding that there is still a long way to go before al-Assad's government and opposition groups can reach some sort of compromise.
"The public statements are going to be showing that there is much distance between the sides," the U.N. envoy added.