Somalia's transitional government has set up a joint police and military unit to counter attacks by suspected Islamists in the capital, Mogadishu.

Dozens of people have been killed during attacks this year, since Islamists were ousted from the city.

On Sunday, four people died in an explosion near the football stadium, while three policemen were shot dead.

The African Union is planning to send a peacekeeping force to replace Ethiopian soldiers backing the government.

"It is a government plan to fight terrorists and bring them to justice," Deputy Defense Minister Salad Ali Jelle told the AP news agency.

He would not give further details but AP quotes an unnamed government official as saying the Ethiopian-trained unit would be 700-strong.

Weapons

The BBC's Mohammed Olad in Mogadishu says a saloon car exploded near the stadium on Sunday morning killing its four occupants and injuring three bystanders.

It is not clear whether the car was carrying explosives or whether it was shot at by gunmen, our correspondents says.

In a separate incident later in the day, three policemen who were manning a road block were killed when unknown assailants opened fire at them.

Some Islamist leaders vowed to start a guerrilla war after they were driven out of Mogadishu in December.

But no-one has claimed responsibility for the spate of attacks.

But the government blames them on the remnants of the Union of Islamic Courts, saying there are some 3,500 Islamist fighters in the city.

After 16 years without a government, Mogadishu is wash with weapons.

The AU's peace and security committee has set up two working groups top oversee military and financial planning of the deployment of troops into Mogadishu.

But the date of deployment has not been announced.

So far only Uganda, Burundi, Nigeria and Ghana have contributed a total of 4,000 soldiers to the mission, that will replace Ethiopians who have started to withdraw.

Uganda's parliament has approved plans to send 1,500 troops.

The AU wants to eventually send 8,000 troops.

Photo caption

AU troops