Loyalists of Muammar Gaddafi killed at least 17 detainees and arbitrarily executed dozens of civilians as rebels moved into Tripoli, a human rights group said today.

Hundreds of Libyan rebels have stormed Muammar Gaddafi’s main military compound in Tripoli.

NATO carried out some of its heaviest strikes on Tripoli yesterday after it emerged that Britain and France are to deploy attack helicopters in Libya in an effort to break the stalemate in the conflict.

Nato warplanes have bombarded targets in Tripoli with more than 20 air strikes around Muammar Gaddafi’s residential compound early today, in what appeared to be the heaviest night of bombing in the Libyan capital since the Western alliance launched its air campaign against his forces.

Nato air strikes targeted the centre of Muammar Gaddafi’s seat of power early today, destroying a multi-storey library and office and badly damaging a reception hall for visiting dignitaries.