BAIDOA, Somalia - Ethiopian troops moved into a second Somali town on Saturday to protect the country's weak, U.N.-backed government, angering the Islamic militia that controls most of Somalia and causing peace talks to collapse.

About 200 Ethiopian troops, driving in pickup trucks mounted with machine guns, moved into Wajid and took control of the airport, meeting no resistance, witnesses said, speaking on condition of anonymity because they feared reprisals.

Wajid is a U.N. aid base 46 miles southeast of the Somali-Ethiopian border. It is run by a clan-based administration not allied with either the government or the Islamists.

Arab League talks in Sudan on Saturday were supposed to ease the situation in Somalia, where the Islamist militia captured the capital, Mogadishu, from government-allied warlords and then consolidated its control over most of southern Somalia. Both sides signed a temporary cease-fire agreement June 22 and the Islamists formally recognized the government.

But the Islamists walked out of the talks because of the Ethiopian incursion, and the government said it would not attend until it received international guarantees that any agreement would be respected.

"The Somali government has violated the accord and allowed Ethiopian troops to enter Somali soil," said Abdirahman Janaqaw, the deputy leader of the Islamic courts' executive council.

Somalia has been without an effective central government since warlords toppled dictator Mohamed Siad Barre in 1991 and then turned on each other, carving much of the country into armed camps.

Despite eyewitness reports of Ethiopian soldiers by residents and U.N. staff, Ethiopian and Somali government officials continued to insist that no Ethiopian troops were in the country.

"There is not a single Ethiopian solider on Somali soil. I deny that the Ethiopians have taken control of Wajid. Our troops control there," Deputy Information Minister Salad Ali Jeeley told The Associated Press in Baidoa, where the fragile transitional government is based.

Later Saturday, two military helicopters landed at Wajid's airport and stayed, according to one resident, Zakariye Mad Keyr. He said no one knew what they were doing there. No armed group in Somalia possesses a helicopter.

Ethiopian troops first moved into Somalia on Thursday to protect the government, which has been challenged for power by Islamic militants. More than 400 Ethiopian troops entered Baidoa, 150 miles northwest of Mogadishu, and residents said they were taking up positions around the compound of President Abdullahi Yusuf.

The Islamic militia's leader, Sheik Hassan Dahir Aweys, responded by calling Friday on all Somalis to wage holy war against Ethiopia, a largely Christian country that is Somalia's traditional enemy.

Ethiopia's move could give the internationally recognized Somali government its only chance of curbing the Islamic militia's increasing power. But the incursion could also be the pretext the militiamen need to build public support for a guerrilla war.

The United States has accused Aweys of links to al-Qaida, and the Islamic group's imposition of strict religious courts has raised fears of an emerging Taliban-style regime.