European Council President Charles Michel arrived in Tripoli Sunday, as Libya seeks to build a unity government and end a decade of chaos following a NATO-backed 2011 revolt.
No details have been released of Michel's visit, which comes as Libyan leaders try to move towards reconciliation in a UN-backed peace process.
Oil-rich Libya has been torn by civil war since the toppling and killing of dictator Moamer Kadhafi in 2011.
Last month, the foreign ministers of France, Germany and Italy were in Tripoli to meet their Libyan counterpart in a show of support for the war-torn country's newly formed government set to lead Libya to December 24 elections.
The new transitional executive emerged from a complex UN-sponsored process launched in November and its members were confirmed by Libya's parliament on March 10.
Next week, Greek Prime Minister Kyriakos Mitsotakis is expected to visit Tripoli to reopen the country's embassy in the capital after over six years.
France reopened its embassy in Libya last month.
The visit will coincide with that of Italian Prime Minister Mario Draghi.
The North African nation is a major route for migrants trying to reach Europe across the Mediterranean and traffickers have thrived in the lawlessness that followed Kadhafi's overthrow.