Dramatic developments in Libyan stalemate

>>> the other big story we're following here tonight, fallout from a nato air attack that the libyan government says killed one of moammar gadhafi 's sons and three of his grandchildren. today angry mobs set fire to the british and italian embassies in tripoli which prompted britain to expel libya's ambassador to london. nbc's mike taibbi is in tripoli with more on last night's nato strike.

>> reporter: there's no doubt there was an air attack . nato confirmed it. reporters here who are tightly controlled were bussed to the scene to record the damage. two of the four structures at the compound destroyed. blood trails on the floor. a government spokesman says moammar gadhafi 's son, saif al arab, was killed. at the time of the air strike on saturday night, gadhafi and his wife were also reportedly in the compound for a family gathering.

>> he's in good health. he wasn't harmed. his wife also is in good health. she wasn't harmed.

>> reporter: in rebel controlled benghazi, eastern libya, there were celebrations of the news that the strikes had killed members of gadhafi 's family. there are also doubts expressed that gadhafi 's son was actually killed. nato 's commander said all targets were military in nature. that nato had no independent confirmation of casualties or of the identity of any casualties. in fact, though, the air strike was the third in a week that reportedly came close to taking out gadhafi himself. one attack while he was giving a televised speech about a proposed cease-fire with nato . but even with the bombs falling reportedly so near to where gadhafi was speaking, his offer to negotiate with nato did not include even a hint he might surrender power. instead he said, i am not leaving my country. no one can force me to leave my country. that was hours before the latest attack in the intensifying nato air campaign reportedly came close to forcing regime change another way.

>> this was a direct operation to assassinate the leader of this country.

>> reporter: pro- gadhafi demonstrators believe that and believe, too, that their leader has now seen family members killed while escaping with his own life again. mike taibbi , nbc news, tripoli .