The blast targeted a security point at the entrance to Taraghin, 780 km (590 miles) south of Tripoli, but did not cause any casualties, a resident said.
The reported departure of the Russians is another blow to Khalifa Haftar's Libya National Army (LNA).
Haftar, in an audio message addressed to his forces, urged them to battle the "colonial" intervention by Turkey until its defeat, in a reference to one-time Ottoman control of Libya.
Twitter accounts that follow air traffic revealed unusual movements by Turkey’s air force.
Turkey “will not bow to threats by Haftar or anyone else,” Turkey’s presidential spokesman Ibrahim Kalin said separately in an interview on NTV.
The LNA said Turkey was sending “terrorists.” Turkey’s government also said that if Tripoli fell then Europe would face a “terrorist threat,” apparently meaning that locals would resort to terrorism.
Turkish media is celebrating this a great victory. Turkey has recruited poor Syrian rebels to fight in Libya and violates an arms embargo.
The Government of National Accord, backed by Turkey and various extremeist groups, are being challenged by the Libyan National Army, which has backing from Egypt and the UAE, among others.
The screenplay has written itself; all we are waiting for now is the ending.