Agence France Presse reported Tuesday  that gunmen stormed Libya's General National Congress (GNC) as it was preparing to elect a new prime minister.
"Armed men have besieged the congress, but we do not know the motive of the attack," Tahar Mokni told AFP.
"We suspended our proceedings, and the vote has been postponed until next week," he added.
The militants opened fire on the congress, and MPs were evacuated from the building immediately.
Businessman Ahmed Miitig from Misrata and Professor Omar Al Hassi from Benghazi  are the two final candidates for the PM position to replace Abdallah Al Thani who resigned from his leadership post earlier this month over security fears.
Miitig is expected to win the vote, already holding 67 of the 152 votes from the MPs who were present at Tuesday's session. Miitig needs 120 votes to win the leadership seat.
It is not yet clear who the militants were who attacked the congress session Tuesday.
The parliament has come under the Libyan people's severe scrutiny and criticism  who accuse the parliament of corruption and "failing to provide a better life" since the oust of former dictator Moammar Gaddafi