US Secretary of State Pompeo to attend Libya peace talks in Berlin

US Secretary of State Mike Pompeo will take part in this weekend's Libya peace conference in Germany and voice support for truce efforts, the State Department said Thursday.

A US official said that Pompeo would call for the withdrawal of all foreign forces from the war-ravaged nation and a resumption of the UN-backed peace process - but that the first priority was preserving a fragile truce.

"The imperative would be the continuation of the ceasefire," the official told reporters on condition of anonymity.

Rogue Libyan Khalifa General Haftar walked away from talks in Moscow this week without signing a permanent truce orchestrated by Russia and Libya.

But German Foreign minister Heiko Maas flew to Benghazi to see Haftar and said the general had agreed to join the Berlin talks and abide by the ceasefire.

The United States backed the European-driven military campaign on behalf of rebels toppled Libyan dictator Muammar Al-Gaddafi in 2011 but more recently has played a low-key role.

Comment: Opposing Libyan sides vie for US support from a capricious White House

Other foreign powers have become increasingly active in the civil war, with Turkey backing the internationally recognized Government of National Accord (GNA) in Tripoli and Russia, Saudi Arabia and Egypt among the supporters of Haftar, who has launched a deadly bid to take the Libyan capital.

The United States officially backs the GNA but maintains contacts with Haftar, whom President Donald Trump praised after a telephone call last year.

Haftar on Thursday paid a surprise visit to Athens, which is angered it was not invited to Berlin and is engaged in a dispute with Turkey over energy claims involving Libya.

The US official declined to comment on Greece's exclusion, saying the decision was up to Germany.