The UK, the US and France have begun attacking Libya as enforcement of the UN-mandated no-fly zone gets under way.
Pentagon officials say the US and the UK have fired more than 110 missiles.
Libyan leader Col Muammar Gaddafi has said he will open arms depots to the people and the interests of Mediterranean countries will be in danger from now on.
Western planes bombed targets in the capital, Tripoli, said the AFP news agency, quoting witnesses and state TV.
Earlier on Saturday, pro-Gaddafi forces attacked the rebel stronghold of Benghazi despite declaring a ceasefire a day earlier.
A French plane fired the first shots against Libyan government targets at 1645 GMT, destroying a number of military vehicles, according to a military spokesman.
UK Prime Minister David Cameron confirmed that British planes are in action over Libya.
US President Barack Obama, speaking during a visit to Brazil, said the US was taking “limited military action” as part of a “broad coalition”.
“We cannot stand idly by when a tyrant tells his people there will be no mercy,” he said.
He repeated that no US ground troops would take part.
Shortly after the bombing started, a Libyan official went on TV to denounce the “barbarian aggression”.
Col Gaddafi himself made a brief speech on Libyan radio, calling on people to resist.
“Civilian and military targets in the air and sea will be liable to serious danger in the Mediterranean,” he said.
Read the link for an in-depth, LIVE analysis -
bbc.co.uk/news/world-africa-12796972