Libya’s national anthem rang out as an evening of celebrations got underway, the first of several to mark 40 years of Muammar Gaddafi’s rule.
Although no western leaders have so far accepted invitations to join the festivities, prominent African and Arab figures are reportedly there.
Gadaffi has kept a tight grip on the country since seizing power in a coup in 1969.
Relations with the west hit a low point in the 1980s when demonstrators sacked the US embassy in Tripoli, and later Washington ordered the bombing of the Libyan capital .
Since then Libya has cut support for armed revolutionary groups and made peace with Washington by scrapping a nuclear weapons programme.
However the recent images of Gadaffi warmly welcoming the Lockerbie bomber on his return to the country has caused outrage in the US and Britain.
But one of the reasons for the six-day celebration is to show the world that the long-isolated oil exporter is open again for business after years of heavy sanctions.