Mogadishu, Somalia ? Hundreds of government soldiers attacked Islamic insurgents across the Somali capital amid heavy artillery shelling Friday, battling along streets strewn with bodies as they tried to regain lost ground.

The U.N.-backed government, which held just a few blocks of Mogadishu before the fighting erupted early in the day, claimed it had taken rebel-controlled areas, but the insurgents said they repelled the attacks.

One Somali reported a busload of fleeing civilians was hit by gunfire, and others told of seeing many casualties. At least 22 people were dead and more than 150 wounded across the city, residents, medical officials and an independent radio station said.

“We are running out of beds … we cannot cope,” said Ali Adde, deputy director of the Medina Hospital, where more than 100 casualties were brought.

Some of the patients were being treated outside in hastily erected tents after the hospital ran out of room, he said.

The government offensive followed a few days’ lull after Islamic insurgents staged a major attack in Mogadishu. Despite successes, the insurgents failed to gain control of key installations like the airport and presidential palace, which are guarded by African Union peacekeepers.

The Islamic fighters also had been expanding their hold on territory in central Somalia taken from clan militias allied to the government.

But the militants halted when neighboring Ethiopia moved several columns of troops over the border to secure key towns. Ethiopia, which helped government troops drive Islamic militiamen out of the capital late in 2006, worries about the insurgents’ links to rebel groups on its own soil.

Regional leaders issued a hurried statement Friday in support of the beleaguered U.N.-backed government, which took advantage of the calm in recent days to resupply and regroup its troops before launching Friday’s assault.

Both sides fired mortars, rocket-propelled grenades and missiles mounted on trucks into residential areas.