Moammar Gadhafi's troops launched a powerful assault with tanks and rockets Friday on Misrata, the last major rebel city in western Libya, sending residents fleeing to increasingly crowded safe areas of the city that are still out of the Libyan leader's reach, witnesses said.
Misrata has become emblematic of the limits of NATO's air campaign, with the alliance's top military commander saying he needs more precision attack aircraft to avoid civilian casualties in urban combat. President Barack Obama acknowledged in an interview that the two-month-old civil war has reached a stalemate.
After a weeklong flurry of high-level diplomatic meetings in Europe and the Middle East, rebel leaders complained that the international community is not doing enough to keep Gadhafi's troops at bay. In the capital of Tripoli, a government official denied Libyan troops are shelling Misrata and said they are only taking defensive actions.
Friday's fighting in Misrata _ even as a NATO foreign ministers meeting in Berlin debated handling of the Libya air campaign _ highlight rebel worries that international intervention won't come fast enough or will be ineffective.
"Time is critical, especially for the people in the west part of the country, especially in Misrata," said Mustafa Gheriani, a spokesman for the rebels who seized much of eastern Libya from Gadhafi at the start of the war. "Is there something else on the diplomatic ground that they know that we don't to put more pressure on Gadhafi? The guy is still shelling and killing and it makes no difference to him."
Rights groups have warned that the situation in Misrata, Libya's third-largest city, is dire after 50 days of siege by Gadhafi's troops. Hospitals are unable to cope with growing numbers of casualties, including many shrapnel injuries.
Rebels in Misrata alleged that Gadhafi's forces have been using cluster bombs, which pose particular risk to civilians because they scatter small bomblets over a wide area. New York-based Human Rights Watch reported Friday that such munitions were used, saying its researchers inspected remnants and interviewed witnesses.
Libyan government spokesman Moussa Ibrahim denied the use of cluster bombs. "Absolutely not," he said when asked about the allegations. "We can never do this. We challenge them to prove it."
U.S. Secretary of State Hillary Rodham Clinton said she was unaware of the reports about the use of cluster bombs.
"I have to say I am not surprised at anything that Col. Gadhafi and his forces do, but that is worrying information and it is one of the reasons why the fight in Misrata is so difficult," Clinton said. "It is at close quarters, it is in amongst urban areas and it poses a lot of challenges to both NATO and to the opposition."
An international aid group evacuated nearly 1,200 migrant workers from Misrata by boat Friday, saying nearly all were weak, were suffering from dehydration and needed medical attention.
The migrants are among 8,300 foreign laborers stranded near Misrata's port without shelter or adequate food and water, and the boat will quickly make a second run to rescue more, said the International Organization for Migration.
Germay Haslan, an IOM coordinator, said he heard the sound of shelling and mortar fire while the ship was in port.
In Friday's assault, a helicopter circled over Misrata for several hours, apparently spotting targets for artillery. Pro-Gadhafi forces bombarded the city with fire from tanks, artillery and rockets, a resident said.
"We've been hearing explosions all day," said the resident, who spoke on condition he be identified only by his given name, Abdel-Salam, for fear of retaliation. Abdel-Salam said the shelling continued until nightfall, portraying the assault as the heaviest since the start of the siege.
Gadhafi's men are in control of the city center, while the rebels are clinging to positions in the port area. Al-Jazeera satellite TV showed video of two armored vehicles parked in a debris-filled street of Misrata.
Gadhafi loyalists have been firing randomly from their positions in the city, forcing people to leave their homes, said a city resident. Once a building is empty, it is being taken over by government troops, said the resident, who spoke on condition of anonymity for fear of retribution. He said government troops have also targeted groups of civilians in the streets, including people standing in line outside a bakery.
He said rebel-held neighborhoods are becoming increasingly crowded. "Now you can find houses with more than 10 families in one house," he said.
Taki Ali, a 43-year-old Iraqi engineer, had moved three times in Misrata because of the shelling. Ali, his wife and two toddler sons had stayed with a Libyan family near the port for two weeks, before being evacuated by boat Friday.
Eight bodies of civilians were taken to a hospital, Abdel-Salam said, adding that he believes there are additional casualties among the fighters.
"Where is NATO?" asked Abdel-Salam. "Their top mission is to protect civilians, and Misrata is the No. 1 city in Libya that needs protection for the civilians."
The alliance is struggling to overcome differences, with Britain and France seeking more strikes by other NATO nations, particularly the U.S. Washington says it sees no need to change what it calls a supporting role in the campaign and many other NATO nations have rules preventing them from striking Gadhafi's forces except in self-defense.
Beyond the political constraints, NATO needs more precision attack aircraft to avoid civilian casualties as Gadhafi's forces camouflage themselves and hide in populated areas to avoid Western airstrikes, said NATO's top military commander, U.S. Navy Adm. James Stavridis.
The commander is looking for about eight to 10 additional planes, said U.S. officials on condition of anonymity because they were not authorized to discuss the details.
The international community stepped into the Libyan conflict a month ago, with NATO unleashing airstrikes on Gadhafi-linked military targets. On Friday, airstrikes struck Gadhafi's hometown of Sirte in eastern Libya. Explosions also were heard from what appeared to be NATO strikes against Gadhafi's forces near the coastal town of Brega.
Obama said in an interview with The Associated Press that a military stalemate exists, but that the U.S. and NATO have averted a "wholesale slaughter" and that Gadhafi is coming under increasing pressure to leave.
Gadhafi is "getting squeezed in all different kinds of ways" and is running out of money and supplies, Obama said. He added that he is confident Gadhafi ultimately will be forced to surrender power and that there is no need for a change in U.S. policy at this time.
There has been mounting international pressure on Gadhafi to step aside after 42 years in power.
Obama, British Prime Minister David Cameron and French President Nicolas Sarkozy wrote in a joint newspaper opinion article that while their mandate under a U.N. Security Council resolution does not include removing Gadhafi by force, "it is impossible to imagine a future for Libya with Gadhafi in power."
However, Gadhafi has been digging in.
On Friday, Tripoli residents reported unprecedented security measures in the capital to prevent anti-government protests after noon prayers, the highlight of the Muslim religious week.
A local journalist said large numbers of Gadhafi loyalists, including women, fanned out across the city, searching cars. Anti-aircraft guns were stationed in several streets, near mosques and main squares, he said.
"This is to scare people," said the journalist. "All worshippers went straight home at the sight of that."
On Friday afternoon, sustained bursts of gunfire were heard in the city, mixed with honking car horns and shouts of "God is great," apparently as part of pro-Gadhafi marches. The government has restricted the movement of foreign journalists in Tripoli, barring them from leaving their hotel without an escort.
The rebels acknowledge that their forces _ defected army units and armed civilians _ can't defeat Gadhafi on their own. Mustafa Abdul-Jalil, head of the rebels' National Transitional Council, said this week that without NATO airstrikes, even Benghazi, Libya's second-largest city and the rebels' main stronghold, would be in "complete danger."
"We have rocket launchers that don't work because they don't have batteries," said Awad Sathi, a 36-year-old soldier who defected to the rebels. "Without the batteries, it's just a pile of junk."
Clinton said the opposition "needs a lot of assistance on the civilian, organizational side, on the humanitarian side and on the military side."
"There have been a number of discussions about how best to provide that assistance, who is willing to do what," she added. "We're also looking at how the opposition could sell oil from sites that are under their control."
Highlighting the rebels' dependence on NATO, a regime force of tanks and armed pickup trucks moved on Ajdabiya this week, some even entering the city before airstrikes halted the advance.
Rebel fighters say only more airstrikes can tip the balance quickly.
"I don't think Gadhafi's forces are weakened, but he doesn't have the freedom to advance," said Lt. Muftah Omar Hamza, who commands 70 rebels. "Even if they destroy 50 percent of Gadhafi's forces, the other 50 percent is stronger than our force."
Western countries insist that the U.N. resolution authorizing intervention would not permit them to send ground troops _ which the rebels don't want anyway.
NATO hopes that, during the military stalemate, economic and political pressure will build on Gadhafi, sparking further uprisings, defections from his regime or even an assassination by a close aide.
Hubbard reported Benghazi. Also contributing were Associated Press writers Maggie Michael in Cairo, Sebastian Abbot in Ajdabiya, Libya, Matthew Lee in Berlin and Ben Feller in Washington.