Ethiopian jets have bombed two airports in Somalia in a widening operation against an Islamic militia group.
The Islamic militia remains in control of Mogadishu airport
Jets hit the international airport in the capital, Mogadishu, and another at Balidogle, in the south of the country.
The Union of Islamic Courts (UIC) has been fighting Somalia's weak interim government and its Ethiopian backers.
Ethiopia's prime minister has said his country is "at war" with the Islamists, and the Red Cross has urged all parties to protect civilians from harm.
Thousands of Somalis have fled the escalating violence, and the Red Cross says the fighting is straining an already weak support system in the country.
Red Cross official Pedram Yazdi told the BBC that the organisation was treating 445 people injured during the fighting, including combatants and civilians.
Aircraft are taking some two tonnes of supplies into Somalia from Kenya each day in an effort to keep hospitals adequately supplied, he said.
Two senior leaders of the UIC, Sheikh Hassan Dahir Aweys and Sheikh Sharif Sheikh Ahmed, landed at Mogadishu shortly after the Ethiopian air strike, a clear sign that the attack did not disable the runway.
The airport was recently reopened by the UIC - which holds most of central and southern Somalia.
The Ethiopian government said it hit the two airports to stop "unauthorised flights", the AFP news agency reported.
The BBC's Adam Mynott, in the region, says Ethiopia is carrying through its threat to hit Islamist positions in pursuit of what it claims is self-defence.
A spokesman for the UIC, Abdirahman Janaqow, told the Associated Press that the Islamists would stand firm against Ethiopia.
"We will overcome the Ethiopian troops in our land. Our forces are alert and ready [to] defend our country," he said at Mogadishu airport.
As Ethiopia struck, Somali and Ethiopian troops captured a checkpoint outside the flashpoint town of Beledweyne.
UIC forces then left the town, the scene of sustained fighting on Sunday.
"Many, many people - children and women - have evacuated last night, and they are in the bush, while others chose to stay in the town," Abdullahi Warsame, Somalia programme manager for the aid charity Save the Children, told the BBC.
Mr Warsame was in Beledweyne as the town changed hands.
"Those who have hidden in some places in the bush... they started to come back with donkey carts, and others who have gone very far towards the town of Bulo Burto - still they have not come back."
There were also reports of heavy fighting at the central flashpoint of Burhakaba, close to the seat of Somalia's transitional government in Baidoa.
Fresh fighting between Somali government forces and the UIC erupted last week.
On Sunday Ethiopia admitted for the first time its troops were fighting in Somalia and began attacking the UIC across a 400km (250 mile) front line along the border.
PM Meles Zenawi said Ethiopia was forced to defend its sovereignty against "terrorists" and anti-Ethiopians.
"We are not trying to set up a government for Somalia, nor do we have an intention to meddle in Somalia internal affairs. We have only been forced by the circumstances," Mr Meles said.
Aid agencies have warned of the civilian cost of fighting
"We want to end this war urgently and we hope that Ethiopian people stand by the defence forces."
The UIC, which has seized control of much of southern and central Somalia, says Ethiopian troops have been fighting alongside government forces for months.
The Islamist group - which controls most of the south, including the capital, Mogadishu - on Saturday appealed for foreign fighters to join its troops in a "holy war" against Ethiopia.
The UN estimates that at least 8,000 Ethiopian troops may be in the country, while rival Eritrea is said to have deployed some 2,000 troops in support of the Islamic group.
Are you or anyone you know near conflict zone? Please send us your experiences and contact details using the post form below.
The BBC may edit your comments and not all emails will be published. Your comments may be published on any BBC media worldwide.