George Bush said on Tuesday the seaports arrangement was "a legitimate deal that will not jeopardise the security of the country."
"After careful review by our government, I believe the transaction ought to go forward," Bush told reporters who had travelled with him on Air Force One to Washington.
"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."
Bush called reporters to his conference room aboard Air Force 1 after the plane had landed on his return from a speech in Colorado. His message dealt with a controversy that is becoming a major headache for the White House.
Only hours before Bush spoke, the leader of the Bush's
Republican Party in the US Senate asked the administration to stop the transaction, under which a British company that has been running six US ports would be acquired by Dubai Ports World, a state-owned business in the United Arab Emirates.
The US Senate majority leader called for Dubai Ports World's takeover of operations at six major US ports to be delayed, saying the deal raises serious questions regarding the "safety and security of our homeland".
Bill Frist threatened to sponsor legislation to review the deal, involving UAE state-owned ports operator Dubai Ports World, despite its go-ahead by the White House.
The Dubai Ports World is owned
by the UAE government
"The decision to finalise this deal should be put on hold until the administration conducts a more extensive review," Frist said in a statement, adding that the deal could have "a major impact on Americas security".
Frist's call came as furore mounted in the US over the deal, with US politicians calling to cancel it and a US company filing suit to block it.
According to media reports, the lawsuit was filed by Miami-based Continental Stevedoring and Terminals Inc against the $6.8 billion takeover by DP World of Britain's Peninsular and Oriental Steam Navigation Co (P&O), which operates the US ports.
Continental, P&O's Miami affiliate, charged that its sale to the Dubai company would force it to become an "involuntary partner" with Dubai's government and even "may endanger the national security of the United States".
The port of Miami is one of America's busiest and is the focal point for its bustling cruise and vacation industry. Other ports affected in the deal are in New York; New Jersey; Baltimore, Maryland; New Orleans, Louisiana; and Philadelphia, Pennsylvania.
The controversy has rocketed to the top of the US political agenda, as Democrats and Republicans have joined forces to try to upend it, criticising what they describe as the UAE's spotty record in combating terror.
Other allies of Bush have parted company with their party's leader on the issue.
Peter King, the Republican chairman of the Homeland Security Committee in the House of Representatives, told US television on Monday that he was "very concerned" about the deal, saying it was "irresponsible ... to have a company which could have an al-Qaida infiltration actually inside those ports, knowing what our security procedures are, knowing what's done in those ports".
However, federal government officials said that they had carefully vetted the deal and that it posed no security risk.
Frist (R), the Senate majority
leader, wants the deal delayed
The deal has been approved by the Treasury Department's Committee on Foreign Investment in the United States.
"There is no higher priority for the members of this committee than protect the security of the United States," said Tony Fratto, Treasury spokesman. Committee members, he added, "take the job very very seriously" and did "thorough work".
Michael Chertoff, the homeland security secretary, told CNN on Sunday that the transfer of ports management had been given "a very thorough review and where appropriate necessary conditions or safeguards have to be put into place".
He said it was important to prevent rigorous security measures from interfering in the free market.
"We have to balance the paramount urgency of security against the fact that we still want to have a robust global trading system," Chertoff said.
House member King, however, disputed the notion that the review had been thorough.
"The fact is that this was a very compressed investigation. The most was 20 to 25 days and only a few days was spent on looking at the security aspects."
DP World's acquisition of the Peninsular and Oriental Steam Navigation Company is to be finalised on 2 March.