The toll of dead and injured was given at a news conference in Tripoli by Government Spokesman Mussa Ibrahim.
"Since March 19, and up to May 26, there have been 718 martyrs among civilians and 4,067 wounded -- 433 of them seriously," Ibrahim said, citing Health Ministry figures.
He said these figures do not include Libyan military casualties, a toll the Defense Ministry refuses to divulge.
Soon after he spoke, 4 powerful explosions rocked the centre of Tripoli, the target of more and more intensive air raids by NATO warplanes for more than a week.
Ibrahim ruled out Kaddafi stepping down from power. "If he goes, the security valve will disappear," he said. "Kaddafi’s departure would be the worst case scenario for Libya," he told reporters, and warned of civil war.
Ibrahim also denied that South African President Jacob Zuma, who met Kaddafi in Tripoli on Monday, had discussed an "exit strategy" with him.
Earlier, a statement from the South African Presidency in Pretoria said Kaddafi would not leave Libya despite growing international pressure and intensified NATO strikes on his regime.
"Colonel Kaddafi called for an end to the bombings to enable a Libyan dialogue. He emphasized that he was not prepared to leave his country, despite the difficulties," Zuma's office said in a statement.
The South African President said raids by NATO, which is enforcing a no-fly zone over Libya and protecting civilians from a government crackdown under a UN mandate, were undermining African mediation efforts.
Source: Agence France Presse - AFP