Libyan rebels say they are advancing in Brega, a key oil port that has been the scene of recent clashes between the opposition and forces loyal to leader Moammar Gadhafi.

The rebels said Thursday that they had gained control of several residential districts of the port, which is about 750 kilometers east of Tripoli.

There are also reports of clashes between the two sides in a western region near the city of Misrata.

In a separate development on Thursday, the European Union stepped up pressure on Mr. Gadhafi's government by expanding sanctions against Libya. The EU imposed restrictions on the al-Sharara oil company and an administrative affairs organization with ties to the Libyan government.

The Libyan uprising began in February. The Gadhafi government has been widely criticized for responding to unrest and pro-democracy demonstrations with a fierce crackdown.

NATO has been carrying out air attacks against pro-Gadhafi forces in Libya since March. On Thursday, the French News Agency quoted the NATO commander of Libyan operations as saying Mr. Gadhafi's forces have been weakened and are “no longer able to launch a credible offensive.”