Col Muammar Gaddafi has made a speech vowing death or victory in the fight against "aggression", after Libyan rebels seized his Tripoli compound. In the audio speech, the colonel, whose whereabouts remain unknown, said he had made a "tactical" retreat from his Bab al-Aziziya compound in the capital. But nobody really believes the claim, a BBC correspondent in Tripoli says. The compound fell on Tuesday to the rebels, who set about demolishing symbols of Col Gaddafi's rule. There were pro-rebel celebrations on the main squares in Tripoli and Benghazi late into Tuesday night but many people are reluctant to celebrate openly until Col Gaddafi and his sons are captured, the BBC's Wyre Davies reports from the city. At one stage, our correspondent and others had to flee from the ruins of Bab al-Aziziya when snipers opened fire from within. Wednesday morning saw what appeared to be new Nato air strikes in and around Tripoli, our correspondent adds. Known pockets of resistance in the capital include the Abu Salim and al-Hadba districts, and near the Hotel Rixos, where 35 foreign nationals, most of them journalists, have been confined by pro-Gaddafi forces. Fighting has also been reported in the southern desert city of Sebha which has strong Gaddafi family connections. 'Martyrdom or victory' In a radio speech rebroadcast on a Libyan satellite TV channel, Col Gaddafi pledged "martyrdom or victory" in the fight against Nato and the Libyan rebels. He said his compound had already been destroyed by what he said were 64 Nato air strikes. Gaddafi spokesman Moussa Ibrahim also spoke to Al-Urubah TV, saying 6,000 volunteers had arrived in Libya to fight for Col Gaddafi. There was no independent confirmation of the report. It is not known if Col Gaddafi and his family were in Bab al-Aziziya on Tuesday when it was attacked. The Gaddafi family are believed to have access to numerous safe houses in Tripoli and beyond, and the situation is unclear in the colonel's hometown of Sirte, which has been a stronghold of his loyalists. Fighting has been reported in Sebha, 650km (400 miles) south of Tripoli, since the rebels moved into the capital. Sebha has a significant military and air force base and, if Col Gaddafi can reach it, it would provide him the option of easy desert escape routes into neighbouring Niger and Chad, according to the Associated Press news agency. A rebel spokesman told the BBC negotiations were going on with people in Sebha and Sirte for a peaceful end to the conflict.