Several issues remain to be ironed out before President Bush officially approves a deal that will enable Japan to build an advanced version of the F-16 fighter plane, the chief White House spokesman says.

Press secretary Marlin Fitzwater said Thursday the administration wants to go ahead with the controversial technology transfer agreement involving the FSX warplane, which Japan wants to deploy in the late 1990s.But, he said, "there are at least three or four basic issues regarding the agreement" that still must be resolved.

Fitzwater, speaking with reporters on Air Force One as Bush flew to Houston for a speech, said a final presidential decision on the FSX may not come until next week.

He said Bush was reviewing documents and reading position papers while on the plane. Once the president decides on safeguards, "then we would be able to announce that we are prepared to go ahead with an agreement," Fitzwater said.

"What he's deciding are the terms of the agreement that we would want to strike for the co-production of the plane," the spokesman said.