Russian Foreign Minister Sergei Lavrov on Sunday said Moscow has evidence that Turkish soldiers have entered Syrian territory.
In his comments to Ren-TV, which were cited by Reuters, Lavrov accused Ankara of conducing a "creeping expansion" on the border with Syria.
He also said Russia would demand that the UN invite Kurds to Syria peace talks despite the opposition of Turkey, which has busily been bombing Kurdish forces.
On another note, Lavrov said Russia is open to coordinating military actions in Syria with the US to recapture the city of Raqqa. Russia has been fighting in Syria for the last several months to prop up Bashar al-Assad's regime, which has been gaining ground against rebels backed by the West and Turkey.
Turkey and Russia have been in a state of open tension, ever since Ankara shot down a Russian fighter jet on the border last November killing two Russian officers. In response, Russia issued vast sanctions on Turkey dealing serious financial damage.
The EU foreign policy chief late last month warned that the conflict risks spilling over into a "hot war" between Russia and Turkey, as the conflict in Syria may turn into something "bigger."
Turkey has discussed sending troops into Syria together with Saudi Arabia as part of the US-led coalition against Islamic State. In response, Russia has warned that if Turkey and Saudi Arabia follow through on their statements on a ground offensive in Syria, it would cause a "world war."