Anti-aircraft fire quickly punctuated the darkness, and then fell silent again.

In Ajdabiya, about 430 miles (700 km) south-southeast of the capital, the British Ministry of Defense on Friday reported airstrikes on "Libyan armoured vehicles which were threatening the civilian population."

The latest military action marks a sixth consecutive night of pounding by coalition jets and came after NATO members agreed to take over enforcement of the no-fly zone over Libya.

NATO also has sent a directive to its military chain of command asking for a plan on how to execute an expanded role for enforcement of UN Resolution 1973, according to NATO sources. Under what some officials were calling "no-fly plus," NATO would be given more robust rules of engagement to ensure that civilians are protected, the sources said.

UN Secretary-General Ban Ki-moon said on Thursday he has seen no signs of the cease-fire called for under U.N. Resolution 1973, which was hurriedly passed March 17 as Libyan forces were closing in on the rebel stronghold of Benghazi.

Ban sent envoy to Friday's African Union meeting in Addis Ababa, Ethiopia, at which representatives of the Gadhafi government and the opposition were expected to attend.