President Bush said Thursday "my conscience is clear" about the Iran-Contra affair and promised to cooperate fully with congressional requests for White House documents dealing with the matter.

However, Bush said it was not clear which documents might still be within his control, suggesting that some have gone to the federal archivists. He said he had no reason to believe that the Reagan administration withheld any documents.Meeting with a small group of reporters at the White House, the president stuck by his earlier refusal to discuss his role in the Iran-Contra affair. But, he added, "Everything I've said, I'll stand behind."

Documents introduced at the trial of former White House aide Oliver North have raised new questions about Bush's involvement, while he was vice president, in the Reagan administration's secret aid to the Contra rebels in Nicaragua.

Bush talked about the Iran-Contra affair and other matters during an informal news conference with nine reporters. He chose an informal setting for the gathering, meeting with the press on the colonnade outside the Oval Office on a sunny spring day.

Bush said he "might have something to say" about the Iran-Contra affair after the completion of North's trial, which was in its final stages Thursday. North is accused of lying to Congress and obstructing a congressional investigation, among other charges.

The president has declined in recent days to field questions on Iran-Contra, saying he didn't want to prejudice the North case. However, he said Thursday, "Let's put it this way, my conscience is clear."

Questions about the Iran-Contra affair focused on the charges that some documents produced in North's trial were not turned over to the congressional committees that investigated the issue.

Bush said he has seen no evidence that all pertinent documents were not made available.