TRIPOLI, Libya — Libyan rebels said today they had control of a post on the Tunisian border, forcing government soldiers to flee over the frontier and possibly opening a new channel for opposition forces in Moammar Gadhafi’s bastion in western Libya.

The reported capture of the border crossing followed three days of intense fighting outside the desert town of Nalut, about 140 miles southwest of the capital Tripoli, said a rebel leader, Shaban Abu Sitta. The area was briefly in hands of anti-government forces last month before Libyan troops moved in.

Holding the Dhuheiba border crossing could open important supply routes for anti-Gadhafi forces and give the rebels another foothold in western Libya.

Meanwhile, in the rebel stronghold of Benghazi in eastern Libya, relief workers and medical teams awaited the arrival of a passenger ferry carrying about 1,000 people out of the besieged city of Misrata, the main rebel holdout in Gadhafi’s territory.