President Bush said this afternoon that he would veto any legislation seeking to block the administration's decision to allow a state-owned company from Dubai to assume control of port terminals in New York and other cities.

Mr. Bush's rare veto threat came as Republican leaders and many of their Democratic counterparts called up today for the port takeover to be put on hold. They demanded that the Bush administration conduct a further investigation of the Dubai company's acquisition of the British operator of the six American ports.

"After careful review by our government, I believe the transaction ought to go forward," Mr. Bush told reporters who were traveling with him on Air Force One to Washington, according to news agencies. "I want those who are questioning it to step up and explain why all of a sudden a Middle Eastern company is held to a different standard than a Great British company. I am trying to conduct foreign policy now by saying to the people of the world, 'We'll treat you fairly." '