Ethiopian troops have reportedly moved into another town in south-western Somalia, two days after entering the country to protect the weak government.
Eyewitnesses say about 200 Ethiopian soldiers took control of the airstrip outside Waajid early on Saturday.
There is no confirmation from either the Ethiopian or the Somali government.
The Union of the Islamic Courts (UIC), a militia which controls the capital and much of the south, has vowed to drive out Ethiopian troops.
The Ethiopians moved into Somalia on Thursday and have been seen in Baidoa, where the beleaguered interim government is based.
Eyewitnesses quoted by the Associated Press news agency say Ethiopian soldiers seized the airport at Waajid, about 70km (43 miles) to the north, before dawn on Saturday.
The town had been controlled by a local militia. It is unclear whether there was any fighting.
Other residents told Somali media that they had seen Ethiopian soldiers in the town centre.
The UIC has pledged to wage a "holy war" to drive out Ethiopian troops.
The Islamic militia drove the warlords from the capital, Mogadishu in June, saying they wanted to restore law and order.
The UIC has since consolidated its power over many parts of southern Somalia.
But Ethiopia is strongly opposed to the militia and has repeatedly warned that it will send its army into Somalia if the government is attacked.
Ethiopia has been a long-term ally of President Abdullahi Yusuf.
UIC leader Sheikh Hassan Dahir Aweys has accused him of being "a servant of Ethiopia".
A UN report earlier this year said that Mr Aweys had been getting significant military aid from Ethiopia's rival, Eritrea - a claim Eritrea has denied.
Mr Aweys has denied US accusations that he and the UIC have links to al-Qaeda.