President Bush is sticking by his plan to gradually phase out bombing exercises on Puerto Rico's Vieques island, despite a local referendum demanding an immediate end.

Bush's spokesman, Ari Fleischer, said Monday the Pentagon needs time to find a new site for exercises under an agreement in which the Navy will withdraw by May 1, 2003, and continue the training on Vieques with dummy bombs until then.

"The president has always said it's very important to listen to the people of Puerto Rico, and he has," Fleischer said. "The president also believes it's very important to have a seamless transition so that our military can be the best trained it can be so we are prepared for any contingencies around the world, and that's the approach that the president will reflect."

Nearly 70 percent of voters in Sunday's nonbinding referendum supported an end to the bombing and the Navy's withdrawal from the island. Thirty percent supported the Navy's remaining indefinitely and resuming bombing with live munitions. Only 1.7 percent backed Bush's plan for the Navy to withdraw by May 1, 2003.

Bush's decision to withdraw within two years "was a recognition of the fact that people of Puerto Rico have concerns on this issue," Fleischer said. "But so, too, is it important to make certain that our military is trained until an alternative is found."

A legally binding referendum is scheduled for November.

"These matters are not only decided by referendum, but they are decided by a variety of factors that represent a balanced approach, and that's what the president has done here," Fleischer said.

Government officials have said the Pentagon will probably need the full two years to make the transition off Vieques.

Bush's decision in June drew criticism from both sides of the issue.

Democrats accused Bush of catering to the growing bloc of Hispanic voters. His top political adviser, Karl Rove, was involved in deliberations that led to Bush's decision.

Republicans in Congress suggest the move could affect military readiness and endanger lives, and possibly set a precedent for other places where there is local opposition to the U.S. military presence.

"The president thinks it's important to listen to the local communities, and he thinks it's important for the United States military to work well with the nations that are hosting us or the localities in this country that have military facilities," Fleischer said. "Very often these communities cherish those military facilities. There may be occasions where they don't and there are some problems, and the president thinks it's very important to work closely with local hosts.

"But it's always a question of balance and working well with local hosts and securing the military needs of our country to have our men and women properly trained so they can deter war," he said.