The Pentagon's African Command said that it had "verified photographic evidence" that the Wagner Group, a private security operation allegedly sponsored by the Russian government, planted the mines "indiscriminately" around Tripoli and toward Sirte east of the capital since mid-June.

"The Russian-state sponsored Wagner Group is demonstrating a total disregard for the safety and security of Libyans," Africom operations director Major General Bradford Gering said in a statement.

"The Wagner Group's irresponsible tactics are prolonging conflict and are responsible for the needless suffering and the deaths of innocent civilians. Russia has the power to stop them, just not the will."

The US has repeatedly accused Russia of introducing military weaponry, including at least 14 MIG-29 fighter jets with their Russian markings covered up, into the Libyan conflict, contravening the UN arms embargo.

Russia, mainly through the Wagner group, and the United Arab Emirates and Egypt, have backed the strongman of eastern Libya Khalifa Haftar, in his fight to seize power from the UN-recognized Government of National Accord in Tripoli.

Turkey's military support for the GNA has recently tipped the balance and allowed its forces in June to repel Haftar's 14-month advance on Tripoli and launch a counteroffensive.

The frontline has since moved east to Sirte.