Ajdabiya, Libya ? Moammar Gadhafi’s forces poured rocket fire after dawn Saturday into Misrata, the only western city still in rebel hands, and weary residents who have endured more than a month of fighting angrily lashed out at NATO for failing to halt the deadly assault.

Five civilians were killed in a 30-minute barrage of shelling that heavily damaged a factory for dairy products and sent up a thick column of black smoke, a doctor said. A human rights group has accused the Gadhafi regime of using cluster bombs in Misrata — munitions that can cause indiscriminate casualties and have been banned by most countries. The Libyan government and military denied the charge.

In eastern Libya, fierce fighting left seven rebels dead, 27 wounded and four missing as the anti-Gadhafi forces sought to push toward the strategic oil town of Brega, according to Mohammed Idris, a hospital supervisor in the nearby city of Ajdabiya. The battle took place on a road halfway between Ajdabiya and Brega.

Frustration was growing among residents in Misrata, where Gadhafi’s troops have intensified their long siege of the city in recent days. The doctor sharply criticized NATO for failing to break the assault with its month-old campaign of airstrikes.

“We have not seen any protection of civilians,” the doctor said. “NATO airstrikes are not enough, and the proof is that there are civilians killed every day here,” he said.

The theme was echoed in the rebel stronghold of Benghazi, where spokesman Abdel-Hafidh Ghoga told a news conference: “There’s no more room for hesitation or for not standing with determination against what is happening in Misrata and other Libyan cities, because the destruction that Moammar Gadhafi is causing in Libyan cities is great and extensive.”

Rebel fighters in eastern Libya were less critical of NATO. Mustafa Abdul-Jalil, head of the rebels’ National Transitional Council, said this week that without the airstrikes, even Benghazi, Libya’s second-largest city and the rebels’ main stronghold, would be in “complete danger.”

The Misrata doctor said Gadhafi’s forces are taking shelter in residential areas that civilians had fled, apparently confident that NATO won’t risk attacking them there.

But the troops have so far been unable to fully occupy the city of 300,000 people, he said, so instead they are targeting sites such as the dairy plant or the port to prevent the arrival of humanitarian aid.