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 in a move that put earlier U.S. endorsement of him in doubt. 

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.

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

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U.S. 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.

(With input from agencies)