US President Joe Biden's national security adviser met Egypt's President Abdel Fattah al-Sisi on Wednesday for talks aimed at ensuring Libya's December elections go ahead as planned, Sisi's office said.

Jake Sullivan travelled to Egypt as part of a Middle East tour that also includes stops in Saudi Arabia and the United Arab Emirates.

In his meeting with Sisi, they spoke about "organising the Libyan elections" as well as "the withdrawal of foreign troops and mercenaries" from the war-ravaged country and the "unification of its armed forces", the Egyptian leader's spokesman Bassem Radi said.

Sullivan's trip to Cairo comes around two weeks after Egypt separately hosted Libya's interim prime minister Abdulhamid Dbeibah, and eastern Libyan strongman Khalifa Haftar.

US ally Egypt is a key player in Libya, which has been plagued by violence since the 2011 NATO-backed uprising that toppled and killed dictator Moamer Kadhafi.

A UN-led process secured a landmark ceasefire in October last year, raising hopes that elections scheduled for December 24 can bring lasting peace to the country.

Controversy over an electoral law has threatened the process, however.

Parliamentary speaker Aguila Saleh angered critics who charged that he bypassed due process and pushed through legislation favouring Haftar, who suspended his military activities last week in a step that could lead to a run for the presidency.

Sisi and Sullivan also discussed an Ethiopian mega-dam on the Nile that is causing tensions with downstream nations Egypt and Sudan.

The White House said Sullivan would reiterate to Egypt the importance of human rights, after making the release of 10 percent of its military aid to the country conditional on the issue.

AFP