President George W. Bush said Monday that the U.S. is committed to helping victims of the tsunami over the long term, but he did not announce an increase in American aid to the region.

The U.S. has committed $350 million and the U.S. navy is conducting emergency operations in the region. Bush says the first phase of relief operations is over and it will take time to make sure aid money is going where it's needed.

Bush met in the Oval Office with his secretary of state, Colin Powell, who has just returned from a fact-finding trip to the region affected by the Dec. 26 tsunami.

"As the secretary [of state] said yesterday, the government of the United States is committed to helping the people who suffer. We're committed today and we will be committed tomorrow. The outpouring of support from the citizens of our country has been more than heartening," said Bush.

Bush also signalled that the initial crisis has passed. "We're now entering a second phase of providing for rehabilitation," he said.

Some have questioned the depth of the U.S. commitment to the aid effort. Bush did nothing on Monday to clear up the confusion about where the money for the current $350-million pledge will come from, or whether other aid money might be redirected.

When Bush was asked if the U.S. might increase its relief package he said, "Well, we'll see. I think the important thing is to make sure that, as one person noted the other day, that the dollars are demand-driven."

While Bush called both the tsunami and the humanitarian response to it historic events, he also sounded a note of caution about how the aid money will be spent.

"Assess the needs, the intermediate-term needs, and the long-term needs to make sure the money that is available actually achieves a co-ordinated objective," said Bush.

Later, Bush's senior aid official, Andrew Natsios, the administrator of USAID, said bluntly that money is no longer the problem. "I don't think there are going to be further pledges. We have a $950-million UN appeal and $4 billion have been pledged, so we're four times over what the UN has requested."

The United Nations is now co-ordinating the entire relief effort and is setting up an unprecedented follow-the-money trail on the internet.

Soon donors, small and large, will be able to go to a UN website in order to track just how their dollars are getting to those who need them.