(CNN) -- Ahead of a key international conference on beleaguered Somalia, transitional government forces, backed by Ethiopian allies, seized a key southern town that was once a strategic stronghold for Islamic militants.
At the United Nations, meanwhile, the Security Council voted unanimously Wednesday to increase the African Union force in Somalia from 12,000 to 17,731 troops.
The town of Baidoa fell into government hands, said Mohamed Ibrahim Habsade, a Somali member of parliament and an officer leading the fight.
Baidoa lies on a key commodities route, and last year, global aid agencies flew in emergency supplies to the town to help thousands of hungry Somalis fleeing drought-ridden areas.
Al-Shabaab militants abandoned the town in fear as government troops closed in.
Ethiopian as well as Kenyan and African Union forces have been helping Somalia's feeble government rid the nation of Al-Shabaab, an Islamic group allied with al Qaeda that has waged an insurgency since 2007.
The group tried to enforce Islamic law after it took over Baidoa, Somalia's third largest city, ordering women to cover up and, according to local media reports, shooting a man for failing to pray at a designated hour.
Al-Shabaab said Wednesday on its website that the group was making a tactical withdrawal from Baidoa.
The government offensive comes at a time at which Al-Shabaab is believed weakened though still potent.
The Security Council's decision to increase the African Union force in Somalia was intended to step up pressure on Al-Shabaab, said Mark Lyall Grant, Britain's U.N. ambassador.
The resolution also called for a ban on the export and import of charcoal, which the Security Council said was a significant revenue source for Al- Shabaab that exacerbates the humanitarian crisis.
Lyall Grant said the vote marked "an important step" in advance of the London conference on Somalia on Thursday.
That meeting, to which 40 governments and global entities have been invited, is designed to look at a wider approach to tackling Somalia's myriad woes.
On the agenda is chronic conflict and terrorism as well as lawlessness, piracy, hunger and massive numbers of refugees. Most importantly participants are set to address the issue of what happens next when the mandate of the transitional government expires later this year.
Among those attending the London conference are neighboring Ethiopia, Kenya and Uganda as well as the United States, Turkey, the United Arab Emirates, Sweden, the African Union and the European Union.
U.S. Secretary of State Hillary Clinton and U.N. Secretary-General Ban Ki-moon also are expected to attend as are representatives of the World Bank and League of Arab States.
Representatives from Somalia will include leaders of the transitional federal institutions, the mayor of Mogadishu and the president of Somaliland, which seceded from Somalia in 1991.
And on a day when two Western journalists were killed in Syria, Reporters Without Borders reminded those who will attend the conference that Somalia remains the deadliest nation in Africa for journalists.
The organization urged the establishment of "institutions capable of assuring the best possible security and protection for journalists working in Somalia."
CNN's Mick Krever and journalist Mohamed Amiin Adow contributed to this report.