Troops from Djibouti have arrived in Somalia's capital, Mogadishu, to bolster the 9,000-strong African Union (AU) force battling Islamist militants.
It is just the third country to contribute to the AU force, which says it needs extra troops to hold territory gained from the al-Shabab Islamists.
Kenya also says its troops in southern Somalia will join the AU force.
Al-Qaeda-linked al-Shabab is fighting to overthrow the UN-backed interim government.
It is estimated to have between 7,000 and 9,000 fighters and controls many southern and central areas of the country.
In August, it announced a tactical withdrawal from Mogadishu after fierce fighting with AU forces.
But the group has continued to detonate bombs in the city, killing five people in an attack at a busy junction earlier this month.
AU commanders say they need up to 20,000 troops to hold on to Mogadishu.
The BBC's Mohamed Dore in Mogadishu says a plane carrying the Djiboutian troops has landed in the city.
They are said to number 200 and will strengthen the AU force, currently made up of Ugandan and Burundian troops.
Other countries that have failed to fulfil promises to send troops include Nigeria and Malawi.
Djibouti borders Somalia and its people speak the same language.
Kenya sent troops in October to pursue al-Shabab after blaming it for a spate of abductions on its side of the border.
The group denies involvement in the abductions.
Somalia has not had a functioning central government for more than 20 years and has been convulsed by fighting between various militias.
The UN says it is the world's worst humanitarian situation, with famine conditions in three southern areas.
Source: BBC News