Powerful ex-rebel militias from the Libyan town of Zintan gave parliament a tight evening deadline to quit on Tuesday, threatening to kidnap any lawmaker who ignored it.
"We are giving the (General National) Congress, whose mandate has expired, five hours to hand over power," said the militia commanders, indicating a deadline of around 1930 GMT.
Zintan, in the mainly Berber highlands southwest of Tripoli, was one of the bastions of the NATO-backed uprising that ousted and killed veteran dictator Moamer Kadhafi in 2011.
It is where his son and former heir apparent, Seif al-Islam, is held awaiting trial.
The militias issuing the ultimatum included the Al-Qaaqaa and Al-Sawaiq brigades, both nominally loyal to the regular army.