The alliance said the building it struck in Brega was a command-and-control-center.

Outside Brega, better rebel discipline was already in evidence on Sunday.

The two sides have been battling for months over Brega, 750km east of Tripoli.

Fighting raged around Brega's university early on Saturday, rebels said.

Younis launched an attack on Brega in June, only to see it beaten back.

His militia also mans the gates at Brega and other ports along the coast.

Warplanes flew over Brega, followed by the sound of explosions.

Shipping sources said the fighting had closed the oil ports of Ras Lanuf and Brega.

Brega, which is technically open, cannot export due to low oil output at nearby fields.

Others said there was still fighting in Brega itself.

Using the dead water guarantees supplies until October, when summer rains should begin again, Brega said.

On the ground, rebels leading the unprecedented popular revolt pushed their front line west of Brega.

A general view of an oil company in Brega October 20, 2013.

The BBC's diplomatic correspondent Bridget Kendall reports from the rebel side of the front line near Brega.

Libyan television said on Friday that five civilians were killed in NATO attacks on targets in Brega.

A general view of the Sirte Oil Company in Brega October 20, 2013.