The Somali insurgent group al-Shabab has seized control of Baidoa, home of the country's parliament.
Witnesses say al-Shabab took over Baidoa Monday just hours after Ethiopian troops who supported the Somali government finished withdrawing from the town and the country.
Residents had reported heavy fighting ahead of the takeover. There has been no word on casualties.
Most Somali parliament members are currently in neighboring Djibouti for a special session that began Sunday.
Today, the lawmakers voted to double the size of parliament, to 550 members, in line with a peace deal the government reached in October with moderate Islamists.
Hardline groups such as al-Shabab have rejected that deal.
On Sunday, Ethiopian troops completed their pullout from Somalia after fighting the Islamists for more than two years in support of the Somali government.
Many Somalis were concerned the withdrawal would cause a power vacuum, and lead to more fighting. Various Islamist groups have taken control over much of the country in recent months, leaving the government in charge of only Baidoa and parts of the capital, Mogadishu.
The government has been hampered by infighting that led to the resignation of President Abdullahi Yusuf last month.
The lawmakers meeting in Djibouti are scheduled to elect a new president within days, after the new parliament members are seated.
A moderate Islamist group, the Alliance for the Re-Liberation of Somalia, will take 200 of the new seats.
The alliance's leader, Sheikh Sharif Sheikh Ahmed, is on a long list of candidates looking to become Somalia's next president.