Somalia's Islamic courts are denouncing warnings by the United States that they may be planning suicide attacks in Kenya and Ethiopia.

Islamic officials based in Mogadishu call Thursday's warning issued by the U.S. Embassy in Nairobi "baseless." The embassy says it has received threats specifically mentioning the possibility of suicide bombings at prominent landmarks in Kenya and Ethiopia.

The United States has repeatedly expressed concern that Somalia's powerful Islamist movement may have links to the al-Qaida worldwide terrorist network.

The warning Thursday follows the collapse of Somali peace talks this week, which have raised fears of an all out war between the Islamists and the interim government.

Reports from southern Somalia say the Islamists have sent more fighters to sites near Baidoa, the interim government's home base.

A U.S. State Department spokesman Thursday voiced concern about the danger of a wider conflict and appealed to Somalia's neighbors to avoid aggravating the situation.

Diplomats fear that open warfare between the two sides could draw in Ethiopia and Eritrea. Ethiopia has vowed to support the Somali government, while the United States has accused Eritrea of arming the Islamists. Eritrea has rejected that charge.

Meanwhile, in the Somali capital, Mogadishu, hundreds of soldiers from Somalia's last national army joined the Islamists Thursday. Many said they want to defend the country from Ethiopia.

Militia groups loyal to Somalia's Islamic courts have seized control over much of the country's south since winning a battle for Mogadishu in June. Somalia's interim government has international support but virtually no power outside Baidoa.

Some information for this report was provided by AFP and AP.