The United States has decided to take its fight against Usama bin Laden's terror network to Somalia, a senior German official said early Wednesday.

The official, speaking on condition of anonymity, said there was no longer a question of whether to go after Al Qaeda terrorists in the east African nation, but only when and how.

At NATO headquarters in Brussels, Gen. Richard Myers, chairman of the U.S. Joint Chiefs of Staff, said: "We are not going to speculate on any next operation."

When pressed, he added: "Countries that harbor terrorists worry us. Somalia is one potential country, but there are others as well."

At Tuesday's meeting of NATO defense ministers, Defense Secretary Donald Rumsfeld mentioned Yemen and Sudan as countries suspected of supporting terrorism.

And in Yemen that day, Yemeni forces trained and equipped with U.S. funds engaged armed tribesmen in a bid to capture suspected Al Qaeda members, government officials and tribal sources said.

Tanks, helicopters and artillery pounded mountain villages and hillsides in what appeared to be the most serious military operation yet in an Arab country in search of suspects allegedly connected to Al Qaeda.

Earlier this month, nine people identified by aid workers and a regional security official as Americans visited a town in western Somalia, where they met with local faction leaders and Ethiopian military officers.

The official, who spoke on condition of anonymity, said the Americans met with leaders of the Rahanwein Resistance Army, a clan-based faction opposed to Somalia's fledgling transitional government and with Mohamed Saeed Hirsi, the leader of an Ethiopian-backed faction also opposed to the government.

U.S. officials have said the United States is concerned Somalia's lack of central authority makes it an attractive base for terrorists.

Iraq also has been identified by President Bush and other senior administration officials as a potential U.S. target.

At various times, Somalia has been mentioned, along with the Philippines, Malaysia, Indonesia, Tajikstan and Uzbekistan, by Bush administration officials as countries with terrorism problems.

Several African countries called on the United States to avoid military action in Somalia and cooperate with the transitional government, which has expressed readiness to "get rid of any terrorist camps if it was proved they existed on Somali lands."

Their joint statement, issued in Cairo by the Sudanese Embassy, was from the Inter-Governmental Authority on Development, a grouping of east African nations, and the 15-nation Group of Sahel and Sahara States.