TRIPOLI, Libya - Libyan ruler Moammar Gadhafi defiantly vowed to fight to the death in an audio recording broadcast Tuesday after NATO military craft unleashed a ferocious series of nearly 30 daytime airstrikes on Tripoli.

In a phone call to Libyan state television station, Gadhafi angrily denounced the rebels and said he would not surrender.

"We will not kneel!" he shouted in the phone call that appeared to also take state television by surprise. The sound was hastily adjusted to make it louder.

"We will not surrender: we only have one choice to the end! Death, victory, it does not matter, we are not surrendering!" he shouted.

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"We are stronger than your weapons, than your planes. The voices of the Libyan people are stronger than the sounds of explosions," he said, angrily calling the rebels who have risen up against him "bastards."

Minutes after he spoke, another explosion shook the capital as NATO apparently launched another strike. Pro-Gadhafi loyalists also fired a round of celebratory gunfire after his speech, which lasted at least six minutes.

The date of the recording could not be confirmed, but his words suggested it was likely made Tuesday in the capital.

As he spoke, the sound of low-flying military craft could be heard whooshing through Tripoli again and Gadhafi quickly hung up.

Gadhafi has mostly been in hiding since NATO strikes in April targeted one of his homes. Libyan officials said one of his sons, Saif al-Arab, and three of his grandchildren were killed.

Gadhafi's last phone call lasted less than a minute and was in mid-May. He was last seen in a brief glimpse of television footage sitting with visiting South African President Jacob Zuma in late May.

Libyan television said several structures in the Gadhafi compound were badly damaged in Tuesday's strikes. Daylight NATO raids have been rare and signal an intensification of the alliance bid to drive Gadhafi from power.

There were no immediate reports about casualties.

NATO officials have warned for days that they were increasing the scope and intensity of their two-month campaign to oust Gadhafi after more than 40 years in power. The alliance is assisting a four-month old rebel insurgency that has seized swaths of eastern Libya and pockets in the regime's stronghold in the west.