CAIRO (Reuters) - The United States on Friday called on eastern Libyan commander Khalifa Haftar to stop his offensive on the capital held by the internationally recognized government and warned against Russian interference.

FILE PHOTO: A Libyan man carries a picture of Khalifa Haftar during a demonstration to support Libyan National Army offensive against Tripoli, in Benghazi, Libya April 12, 2019. REUTERS/Esam Omran Al-Fetori/File Photo

Haftar’s Libyan National Army (LNA) has been trying since April to take Tripoli, part of a power struggle in the oil producing nation since the overthrow of Muammar Gaddafi in 2011.

He is backed by Egypt, the United Arab Emirates and most recently Russian mercenaries, according to diplomats and Tripoli officials. The LNA denies it has foreign backing.

“The United States calls on the ‘Libyan National Army’ to end its offensive on Tripoli,” the U.S. State Department said in statement late on Thursday after a visit to Washington by the Tripoli-based foreign and interior ministers.

Both sides launched a U.S.-Libyan security dialogue.

“The U.S. delegation, representing a number of U.S. government agencies, underscored support for Libya’s sovereignty and territorial integrity in the face of Russia’s attempts to exploit the conflict against the will of the Libyan people,” the statement said.

It was the strongest U.S. statement since Russian mercenaries were first sighted in Tripoli in September fighting alongside the LNA, which is allied to a parallel government in eastern Libya.

President Donald Trump called Haftar in the first weeks of the offensive, which has failed to breach Tripoli’s defenses, in a move that some diplomats took as sign Washington might be backing the former Gaddafi officer.

Trump “recognized Field Marshal Haftar’s significant role in fighting terrorism and securing Libya’s oil resources, and the two discussed a shared vision for Libya’s transition to a stable, democratic political system,” the White House said at the time.

A parallel central bank in eastern Libya received increased deliveries of new banknotes from Russia this year, Russian customs data showed last month.

While Russia has provided Haftar with support, it has simultaneously cultivated relations with the internationally recognized Government of National Accord in Tripoli.