MOGADISHU - Somali government forces attacked rebel strongholds in Mogadishu on Friday, triggering battles across the capital that killed at least 15 people.

Neighboring states and Western security forces fear Somalia, which has been mired in civil war for 18 years, could become a haven for militants linked to al Qaeda.

Witnesses said four insurgents from the hardline Islamist al Shabaab group died and a journalist from local independent Shabelle Radio was also killed.

Residents scuttled across the dusty streets and sheltered by walls as heavy gunfire shook the capital. Some children milled around near a dead body, its blood draining into the sand.

Fighters wearing headscarves with ammunition belts draped over their shoulders loitered on a corner as a battered 4x4 pickup with a heavy machinegun on top raced past.

The government says there is little hope of negotiating with the Shabaab gunmen trying to topple it. The administration says the rebels have no political agenda and have hundreds of foreign extremists in their ranks.

The opposition groups have been provoking us for the last three weeks, said Defense Minister Mohamed Abdi Gandi.

We shall continue fighting this opposition with foreign ideologies. They want to destroy our government by the use of violence but it will not be, he told reporters.

Sources at two Mogadishu hospitals said they received 85 wounded civilians on Friday, and that four of them later died. Residents in the city's Hodon district said the bodies of six dead insurgents were lying at a police station there.

REBEL STRONGHOLD SURROUNDED

The heaviest fighting for months has killed scores of civilians and uprooted tens of thousands in the last two weeks.

I saw masked men running away carrying the bodies of four of their friends, Halima Osman, a mother-of-three who lives in the city's sprawling Bakara Market, told Reuters.

We were surprised to see men in government uniforms fighting in Bakara. They have recaptured four police stations between here and the palace, and they are advancing further.

Residents said Friday's pre-dawn assaults looked to be a concerted effort by pro-government forces to seize back control of strategic sites. One man said government troops had encircled Bakara Market, al Shabaab's biggest stronghold in the city.

Hassan Mahdi, a spokesman for Hizbul Islam, another Islamist guerrilla group battling the government, told Reuters by telephone that troops had struck at their positions too.

Al Shabaab and Hizbul Islam are counter-attacking ... we have pushed them back in some places. There are casualties, but I can't say how many. We are in the middle of fighting, Mahdi said as heavy gunfire thundered in the background.

Local journalist Abdirizak Warsame was killed in the crossfire as he walked to work at his radio station.

A stray bullet hit him in the head and he died on the spot, Shabelle Radio boss Mukhtar Mohamed Hirabe told Reuters.

Fighting has killed at least 17,700 civilians and driven more than 1 million from their homes since the start of 2007. About 3 million Somalis survive on emergency food aid.

The United Nations refugee agency UNHCR says 46,000 people have fled clashes in Mogadishu in the past two weeks.

Islamist rebels including Shabaab -- which Washington accuses of having close links to Osama bin Laden's al Qaeda -- control much of the south and center of the country.

While they have brought relative security to some areas, the militants' strict interpretation of sharia law has angered some Somalis who are traditionally more moderate Muslims.

Somalia