At least seven people were killed in overnight Friday clashes in Somalia's chaotic capital Mogadishu, witnesses said.

Among the dead were three government soldiers and four insurgents.

Witnesses in south Mogadishu said the fighting started after suspected insurgents hurled grenades at Somali and Ethiopian soldiers on foot patrol, instantly killing the three soldiers.

Face-to-face combat erupted immediately, pitting joint Somali-Ethiopian troops against the Islamist rebels, who were forcefully routed out of the area minutes later.

Witnesses said the dead soldiers' bodies were transported to the ex-ministry of defense compound, while the bodies of the dead insurgents lay on the ground as of Saturday morning.

Thousands of people have been killed in Mogadishu during an ongoing 17-month insurgency against the Somali government and its Ethiopian military backers.

Insurgents capture district

In Bay region, northwest of Mogadishu, al Shabaab insurgents entered the district of Qansah-Dheere and took control without facing any resistance.

Residents said there were no government troops present when the insurgents arrived Friday night.

But a prisons official, Col. Ali Barre, was shot and killed by the insurgents near his home in Qansah-Dheere after they took control of the town.

Somali rebels have seized control of several towns in recent months, but the country's Ethiopian-backed interim government lacks the resources to challenge the rebels at all corners of the country.