Libya's internationally recognised parliament has voted to extend its term beyond 20 October.
The move could complicate efforts by the UN and Western powers to bring an end to the country's protracted political stalemate.
The parliament's spokesman said it was still supporting UN-sponsored talks that resumed in Morocco this week.
Libya has had two rival parliaments and governments, backed by rival militia groups, since last summer.
A loose alliance of militias, including Islamists, seized the capital, Tripoli, in August 2014 and reinstated the General National Congress (GNC), forcing the existing and internationally recognised government to flee to the eastern city of Tobruk.
The move to extend the parliament's mandate was passed by 112 out of 131 MPs.
The assembly had acted to "avoid a vacuum in the country", MP Tarek Juroushi told the Reuters news agency.
Both parties taking part in UN-backed negotiations have been on the fence over the latest draft agreement, which the UN says can no longer be amended, the BBC's North Africa correspondent Rana Jawad reports.
The country's politicians are facing increasing pressure from the West to reach an agreement, she adds.