Russia on Tuesday (local time) said its military units were patrolling the territory in northern Syria which was vacated by Americans.
The Americans had vacated the area following the withdrawal order by US President Donald Trump.
The New York Times reported that it underscored the sudden loss of US influence in the eight-year Syria war. The Americans had until Monday maintained two military bases in the area.
This comes days after Turkey launched an offensive in Syria, a move that has invited international condemnation with several countries suspending their arms sales to Ankara over the issue. The move has also raised fears of a revival of the dreaded terrorist group ISIS.
The US-based newspaper said Russia which is the most important ally of the Syrian government, was moving to fill the security void left by the withdrawal of both the American military and its partners in their effort to destroy the Islamic State and its Syrian base.
President Trump's decision to vacate the area has drawn flak with several accusing him of betraying Kurds, America's ally in its war against ISIS.
Facing criticism for the decision, US President imposed sanctions over Turkey for its military incursions in Syria and called for an immediate ceasefire in the Middle Eastern Nation.
Vice President Mike Pence on Monday said that Trump had called on his Turkish counterpart Recep Tayyip Erdogan to stop operations in northern Syria, reported Sputnik.
( With inputs from ANI )