At least 17 people have been killed and over 45 others injured in heavy fighting that pitted Somali rebel fighters against government troops backed by African Union forces in the restive capital Mogadishu, witnesses and medics said on Wednesday.

The fighting erupted in the capital's Hodan district where government forces carried out surprise attacks on Al-Shabaab positions.

"Mortar shells that landed at our neighborhoods killed several people and injuring more others. It was the worst fighting that I witnessed," said Nasteh Isse, one of Hodan's remaining residents.

However, both sides involved in the violent clashes claimed to have achieved substantial victory.

Somalia's state minister for defense Sheikh Yusuf Mohamed Siad aka Indha'adde said government forces have conquered new positions after driving rebel fighters out of the district.

"We have killed several rebel fighters including senior ones. They (Al-Shabaab) could not even pick up their slain fighters," he told reporters.

In response, Sheikh Ali Mohammed Hussein, Al-Shabaab's Mogadishu boss said they have successfully repelled and dealt a blow to the attacking forces.

Medics at Mogadishu's main hospitals of Medina and Daynile reported that several civilians have been admitted on Wednesday with bullet and shrapnel wounds.

The violence breaks several days of lull in the chaotic capital of the war-torn country.

Tension has been rising over a government-planned onslaught against the rebels in the capital and other parts of the war-torn country. But the offensives seem to have been delayed indefinitely.

Somalia has been without an effective central government since 1991 and, almost half of its population-- 3.8 million people--are in dire need of humanitarian food aid.