There has been more violence in the capital this week
More than 60 people are reported to have been killed and 150 wounded during clashes in the Somali port of Kismayo.
More than 3,000 people have fled the southern city, where an estimated 10 people died on the third day of some of the most intense fighting for months.
A BBC reporter says Islamists have been trying to seize control of the port from a local clan.
There has also been fierce fighting in the Somali capital, Mogadishu, and pirate hijackings off the north coast.
The BBC’s Mohamed Olad Hassan says Kismayo, Somalia’s third city, is strategically important because it serves as a port for the south of the country and for neighbouring Kenya.
The head of a human rights group in the port said the fighting had caused an acute humanitarian crisis.
Many people have no access to food and all business activity is reported to have stopped.
In Mogadishu on Thursday, some mortars landed near the compound of President Abdullahi Yusuf, who was out of the country.
Another landed near a mosque in the busy Bakara market, killing at least six people, a witness told the BBC.
Witnesses said government troops and their Ethiopian allies responded by opening fire, killing several civilians.
At least 20 people were reported to have been killed in fighting in the capital.
Ethiopian troops entered Somalia in December 2006, to oust Islamist forces from Mogadishu.
The police chief in the capital said people who wanted to sabotage talks in neighbouring Djibouti between Somalia’s provisional government and its Islamist rivals were behind the most recent violence, our correspondent reports.
Somalia has been without a functioning national government since 1991 and has suffered ongoing civil strife.
The UN’s World Food Programme is expanding its programme to feed 2.4 million people in Somalia by the end of the year.
Meanwhile, the International Maritime Bureau (IMB) said on Friday that pirates had seized a German cargo ship off the Somali coast a day earlier.
Earlier, a Japanese tanker and an Iranian bulk carrier had been hijacked in the Gulf of Aden, a busy international shipping route to the north of Somalia.
An IMB spokesman said a warship from an international force was tracking the hijacked ships.
Another ship, a Malaysian oil tanker with 39 crew was captured in the same area on Tuesday.