The White House said Wednesday it was skeptical about top Iranian officials' comments welcoming a US-backed reward package aimed at ending the dispute over Tehran's nuclear program.

"If they were serious about wanting to take us up on that offer, then that would be welcome. But I think we have every reason to be skeptical since we get mixed messages from them quite often," said spokeswoman Dana Perino.

"The best way for us to respond to it is to say that we'll see," she said.

Iranian Foreign Minister Manouchehr Mottaki told US journalists Tuesday that Tehran was "seriously and carefully examining" the incentives package and would respond formally in the next "couple of weeks," the Washington Post said.

"We believe that talks are a good foundation for continuing our conversation in this field," the Post quoted him as saying, calling the diplomatic efforts by six major powers a "constructive" approach.

According to the state-run IRNA news agency, Mottaki told US reporters in New York that "a process is underway and it started with the package delivered by Iran."

"This package presented tackled important questions and then on the other side the world powers offered their own package," he said.

Six world powers last month presented Iran with a proposal aimed at ending the crisis which offers technological incentives in exchange for Tehran suspending uranium enrichment, which can be a key step to make an atomic bomb.

Tehran denies that its program hides a nuclear weapons quest. US President George W. Bush has said that he has not ruled out using force against Iran.

The Islamic republic has put forward its own package, a more all-embracing effort to solve global problems and notably suggests the setting up of a consortium in Iran for enriching uranium.

According to IRNA, Mottaki was asked about the question of suspending uranium enrichment. But he did not give any direct comment on the subject.