One person was killed and several injured when militiamen protesting outside the Libyan prime minister's office opened fire.
Witnesses and officials said the militiamen, from Libya's western mountains, were at the prime minister's compound on Tuesday to demand cash from the government when the protest turned violent.
Government spokesman Nasser El-Manee told a news conference one person from the government security forces was killed.
He said three security force personnel and one demonstrator were injured.
Mr Manee said a small group of protesters had arrived in front of the compound, a short distance from Tripoli city centre, in the morning, calling for payment for former fighters, better treatment for the war wounded and other demands.
Government officials, including the defence minister, tried to negotiate with them but the protesters forced their way into the compound, he said.
When forces from the interior ministry arrived and tried to get them to leave, gunfire broke out and all employees inside were evacuated.
Interim Prime Minister Abdurrahim El-Keib was at a meeting elsewhere when the shooting happened.