Forces loyal to Libyan leader Muammar Gaddafi have launched their first bombing raids on the main rebel-held city of Benghazi.

Low-flying aircraft and explosions could be heard on the outskirts of the city and the targets included the city's airport at Benina, the BBC reported.

A rebel spokesman told AFP on Thursday they shot down two aircraft.

The Red Cross has announced that it is withdrawing from Benghazi because of the deteriorating security situation in the city.

Over the last few days Gaddafi’s forces have regained control over several rebel-held cities, including positions around Ajdabiyah and Misrata.

The Libyan Defence Ministry on Thursday threatened to attack foreign security forces stationed in the Mediterranean Sea in retaliation for any foreign military intervention in the country.

"Any foreign military act against Libya will expose all air and maritime traffic in the Mediterranean Sea to danger and civilian and military (facilities) will become targets of Libya's counter-attack," said the statement broadcasted on Libyan television.