WASHINGTON (AP) — As they gear up for a global war on terrorism, America and its close allies could have trouble agreeing — beyond Osama bin Laden — just who is a terrorist. Some nations already warn they will not help the United States if the target is Hamas, Islamic Jihad or Hezbollah. All three are Islamic extremist groups listed by the United States as terrorists and with suspected ties to bin Laden's al-Quaida network. Yet some Arab nations view them as legitimate fighters against Israel.

"Our war on terror begins with al-Qaida, but it does not end there," President Bush pledged to the nation in a speech before Congress on Thursday night. "It will not end until every terrorist group of global reach has been found, stopped and defeated."

That's when some allies may start to get cold feet.

"You have to pick carefully how wide your net is thrown," said Michael O'Hanlon, a defense expert at the Brookings Institution in Washington. "Many countries are not going to share intelligence if they think we're coming after people on their ground, or people they don't want us to come after."

Top U.S. officials answer vaguely when asked how the U.S. might work with two nations they have reached out to — Syria and Iran — that currently are on a list of nations that America says sponsor terrorism.

"We're leaving open the possibilities and we're exploring," the president's national security adviser, Condoleezza Rice, said Sunday. "But let me be very clear. We are not going to declare that there are good terrorists and bad terrorists. There's terrorism. And if you sponsor terrorism, you are hostile to the United States."

In the first days after the Sept. 11 terror attacks in New York and Washington, Secretary of State Colin Powell and others seemed to suggest the United States would go after any group it considered terrorist. That could be more than two dozen, including groups like the Shining Path in Peru and the Basque Fatherland, or ETA, in Spain.

Bush was careful to stress in his speech last week that the fight would target terrorists with global reach, O'Hanlon noted.

The United States needs a strong coalition of nations, especially Arab ones, for a military campaign against bin Laden's suspected terror camps in Afghanistan — considered the almost-certain first target — because it needs somewhere to base airplanes and stage troops.

Intelligence from Arab nations also is needed.

Yet a senior Saudi official, speaking from Riyadh, cautioned that any aid from Arab and smaller Persian Gulf states must be preceded by a clear and specific declaration of which countries and groups will be targeted.

Saudi Arabia and the Gulf emirates will not agree to engage in a conflict with groups that resist Israel in its struggle with Palestinian groups, said the official, speaking on condition of anonymity. He specifically cited Hamas, Islamic Jihad and Hezbollah.

The Arab nations worry their citizens will become outraged if they help America go after groups that resist Israel, said Anthony Cordesman, a Mideast specialist at the Center for Strategic and International Studies in Washington. Since the terror attacks, U.S. officials have pressed both Israel and the Palestinians to contain Mideast violence.

What may happen, said one Middle East expert who teaches at a U.S. defense college, is that the United States will join with Egypt, for example, to go after a few Middle East terrorist groups, but then avoid a public linking with Egypt when it goes after a terrorist group with popular support inside Egypt. He spoke on condition of anonymity.

The Bush administration also may single out groups in order to lure allies. In his speech Thursday, for example, Bush named the Egyptian Islamic Jihad and the Islamic Movement of Uzbekistan, both of which threaten leaders from whom the United States wants assistance, in Egypt and Uzbekistan.

Administration officials have said they are seeking not just military and intelligence assistance, but also diplomatic help and help tracking terrorists' money.

Defense Secretary Donald H. Rumsfeld has acknowledged that the U.S. campaign, no matter how sweeping, cannot stop terrorism altogether.

"We may not eliminate it completely from the face of the earth, which we surely will not," Rumsfeld said. The goal, he said, "is to go after this worldwide problem in a way that we can continue our way of life."