U.S. President Barack Obama said on Sunday that stress tests for the country's top banks would show some need more public help than others, but he vowed not to pour taxpayer money into a black hole.

Different banks are in different situations. They're going to need different levels of assistance from taxpayers, Obama told a news conference in Port of Spain, Trinidad and Tobago, where he was attending the Fifth Summit of the Americas.

The country's top 19 banks are being subjected to a battery of tests to work out how much more stressed their capital and finances would be if the economy got much worse. Guidelines about the process are due on April 24, with results on May 4.

If taxpayer money is involved, I've got a responsibility to ensure some transparency and accountability in the operations of those businesses.

We try to use as light a touch as we can. But I am not going to simply put taxpayer money into a black hole, where you are not going to see results, Obama said.

Scattered U.S. indicators signal that the pace of economic deterioration may be slowing and the country's severe recession nearing an end, but Obama said that conditions remain tough.

We're not out of the woods. This is still a difficult time for the economy. Credit is still contracted, he said.

(Reporting by Alister Bull; Editing by Eric Beech)

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