Somali troops and African Union forces have captured the town of Jowhar from the Islamist militant group, al-Shabab, reports say.
The troops encountered no resistance as the militants had fled, said a military spokesman and residents in the town.
Jowhar was the biggest town under the control of al-Shabab Islamists.
The al-Qaeda linked group has been driven out of most urban areas over the past two years, but still controls many rural areas of the country.
Jowhar, 90km (55 miles) north of the capital, Mogadishu, commands access to Somalia's biggest road linking the southern and central regions of the country. It is also at the heart of a rich agricultural area.
Correspondents say its fall is a major blow to the militants.
"We took control this morning and are now establishing security in Jowhar," a spokesman for the AU mission in Somalia, Amisom, told AFP news agency.
"Amisom troops alongside Somali National Forces entered the town, there was little fighting as the Shabab largely fled ahead of us," Col Ali Houmed said.
AFP quoted an al-Shabab spokesman as saying the militants had withdrawn "for strategic reasons" and remained "close by".
"We will hunt the invaders from inside and outside Jowhar," Abdiaziz Abu Musab said.
Al-Shabab were forced out of the capital, Mogadishu, in August 2011 by African Union troops who, with government forces, went on to take control of most of the militant-held towns.
Alongside the recent military gains, a new Somali president took office in September, raising some hopes of a return to law and order after two decades of anarchy.