WASHINGTON – Lawmakers determined to capsize the pending sale of shipping operations at six major U.S. seaports to a state-owned business in the United Arab Emirates said President Bush’s surprise veto threat won’t deter them.

Bush on Tuesday brushed aside objections by leaders in the Senate and House that the $6.8 billion sale could raise risks of terrorism at American ports. In a forceful defense of his administration’s earlier approval of the deal, he pledged to veto any bill Congress might approve to block the agreement.

The sale’s harshest critics were not appeased.

“I will fight harder than ever for this legislation, and if it is vetoed I will fight as hard as I can to override it,” said Rep. Pete King, R-N.Y., chairman of the Homeland Security Committee. King and Democratic Sen. Charles Schumer of New York said they will introduce emergency legislation to suspend the ports deal.

Another Democrat, Sen. Bob Menendez of New Jersey, urged his colleagues to force Bush to wield his veto, which Bush — in his sixth year in office — has never done. “We should really test the resolve of the president on this one because what we’re really doing is securing the safety of our people.” White House counselor Dan Bartlett said Wednesday the UAE company, Dubai Ports, “is a reputable firm that went through a congressionally approved vetting process.” He said the U.S. has “the necessary safeguards to make sure that the security of our country is in place” and that rejecting the deal would send “a dangerous signal to people overseas that America plays favorites.”

“The president wants this deal to go forward because it was followed by the book and he wants Congress to understand that,” Bartlett said on CBS’ “The Early Show.” He told Fox News Channel that Bush felt strongly that “we need to be adding strategic partners” in the Mideast.

But Sen. Joseph Biden, D-Del., said the bipartisan opposition to the deal indicated “a lack of confidence in the administration” on both sides. “Sure, we have to link up with our Arab friends but … we want to see and those in Congress want to know what … safeguards are built in,” Biden said on ABC’s “Good Morning America.”

The first-ever sale involving U.S. port operations to a foreign, state-owned company is set to be completed in early March. It would put Dubai Ports in charge of major shipping operations in New York, New Jersey, Baltimore, New Orleans, Miami and Philadelphia. “If there was any chance that this transaction would jeopardize the security of the United States, it would not go forward,” Bush said.

Defending his decision, Bush responded to a chorus of objections this week in Congress over potential security concerns in the sale of London-based Peninsular and Oriental Steam Navigation Co.

Bush’s veto threat sought to quiet a political storm that has united Republican governors and Senate Majority Leader Bill Frist of Tennessee with liberal Democrats, including New York Sens. Hillary Rodham Clinton and Schumer.

To assuage concerns, the administration disclosed some assurances it negotiated with Dubai Ports. It required mandatory participation in U.S. security programs to stop smuggling and detect illegal shipments of nuclear materials; roughly 33 other port companies participate in these voluntarily. The Coast Guard also said it was nearly finished inspecting Dubai Ports’ facilities in the United States.

Frist said Tuesday, before Bush’s comments, that he would introduce legislation to put the sale on hold if the White House did not delay the takeover. He said the deal raised “serious questions regarding the safety and security of our homeland.

House Speaker Dennis Hastert, R-Ill., asked the president for a moratorium on the sale until it could be studied further. “We must not allow the possibility of compromising our national security due to lack of review or oversight by the federal government,” Hastert said.

Bush took the rare step of calling reporters to his conference room on Air Force One after returning from a speech in Colorado. He also stopped to talk before television cameras after he returned to the White House.

“I can understand why some in Congress have raised questions about whether or not our country will be less secure as a result of this transaction,” the president said. “But they need to know that our government has looked at this issue and looked at it carefully.”

A senior executive from Dubai Ports World pledged the company would agree to whatever security precautions the U.S. government demanded to salvage the deal. Chief operating officer Edward “Ted” H. Bilkey promised Dubai Ports “will fully cooperate in putting into place whatever is necessary to protect the terminals.”

Bush said protesting lawmakers should understand that if “they pass a law, I’ll deal with it with a veto.”

Lawmakers from both parties have noted that some of the Sept. 11 hijackers used the United Arab Emirates as an operational and financial base. In addition, critics contend the UAE was an important transfer point for shipments of smuggled nuclear components sent to Iran, North Korea and Libya by a Pakistani scientist.