Top Republican lawmakers in the House of Representatives say they are planning legislation that would block a Dubai company from taking over operations of several U.S. ports, setting up a showdown with the White House.

The chairman of a key House committee says he will attach a provision blocking the proposed deal to an emergency spending measure for the war in Iraq and for Hurricane Katrina recovery efforts.

The proposal marks a significant break between the White House and Republican lawmakers who have supported President Bush's legislative agenda in recent years.

The White House has vowed to veto any legislation overturning the deal with Dubai-owned DP World, and on Tuesday a spokesman said the administration would continue to work with Congress on the matter.

But House members say the issue is a "very big" political problem for lawmakers and they expect to hold talks with the Senate on ways to block the takeover.