There is growing concern in the US over a multi-billion dollar deal giving control of ports to an Arab company.
Critics say the deal represents a security threat
Lawmakers have condemned the Bush administration's decision to approve the deal, saying it will make the country more vulnerable to terrorism.
But the US government insists the right safeguards are in place.
The takeover would put six of America's largest ports, including New York and New Jersey, in the hands of Dubai Ports World of the United Arab Emirates.
The ports are currently run by British ports and shipping firm P&O, which has agreed a $6.8bn (£3.9bn) takeover by DP World.
The deal has been approved by the Bush administration, but has alarmed both Republicans and Democrats.
Critics fear an increased risk of terrorist attacks, pointing out that the UAE was the home of two of the hijackers involved in the 11 September 2001 attacks.
The other ports involved in the takeover are in Philadelphia, Baltimore, New Orleans and Miami.
Republican Lindsey Graham, has called for an immediate freeze on the deal and demanded a "full and thorough investigation" of the sale.
He also dubbed the government's support of the deal "politically tone deaf".
Democratic Senator Chuck Schumer said: "The question that needs to be answered is whether or not they [Dubai] can be trusted to operate our ports in this post 9/11 world."
"Should we be outsourcing our own security?"
Opponents of the deal are planning to lodge their protests at a Senate hearing planned for later this month.
New York Governor George Pataki and Maryland Governor Robert Ehrlich said they were investigating their options, including the possibility of cancelling port management contracts.
However, the US government has rejected the concerns, saying the deal was thoroughly vetted, and stressing that the US Coast Guard will remain responsible for port security.
"We make sure there are assurances in place, in general, sufficient to satisfy us that the deal is appropriate from a national security standpoint," Homeland Security Secretary Michael Chertoff told ABC television.
The government also said the UAE was a key ally in the war on terror.
P&O and DP World say they are confident the deal will go ahead, the latter insisting that security was "at the forefront" of its business.
DP World representatives were due to begin meetings with the ports authorities on Tuesday, trying to reassure them.
Britain's Department of Transport said it would not intervene in the deal as it was "a private market issue".