WASHINGTON – In an election-year repudiation of President Bush, a House panel dominated by Republicans voted overwhelmingly yesterday to block a Dubai-owned firm from taking control of some American port operations.

By 62-2, the Appropriations Committee voted to bar DP World, run by the government of Dubai in the United Arab Emirates, from holding leases or contracts at American ports.

Mr. Bush has promised to veto any such measure passed by Congress, but there is widespread public opposition to the deal and the GOP fears losing its advantage on the issue of national security in this fall’s elections.

“This is a national security issue,” said Rep. Jerry Lewis, the chairman of the panel. The California Republican said the legislation would “keep America’s ports in American hands.”

As the committee acted, Democrats on the other side of the Capitol were clamoring for a vote on the same issue in the GOP-led Senate.

“We believe an overwhelming majority will vote to end the deal,” said Senator Schumer, whose attempt to force the issue to the floor brought the Senate to a late-afternoon standstill.

By its vote, the House committee attached the ports language to a must-pass $91 billion measure financing hurricane recovery and wars in Iraq and Afghanistan. The full House could consider that measure as early as next week.

While GOP Senate leaders hope to delay a quick showdown with Mr. Bush on the issue, the House panel, including members of Mr. Bush’s own party, showed a willingness to defy him.

“One of the most vulnerable situations facing America is our ports of entry,” said Rep. Bill Young, a Republican of Florida, chairman of the House defense appropriations subcommittee. “Whoever’s responsible for those ports of entry should be American.”

Rep. Marcy Kaptur, a Democrat of Ohio, said allowing the DP World takeover to proceed – and ignoring the public outcry over it – would be irresponsible. “The American people elected us to do something when an issue like this comes up,” she said.

Only Reps. Jim Kolbe, a Republican of Arizona, and Jim Moran, a Democrat Virginia, voted against the measure.

“It is premature, we don’t have enough information and … it may turn out to be unnecessary,” Mr. Moran said. Added Mr. Kolbe: “I just don’t think this is the right thing to do.”

The House and Senate developments underscored the extent to which the politically charged issue has come to dominate the agenda in recent days, with Republicans and Democrats competing to demonstrate the strongest anti-terrorism credentials in the run-up to midterm elections.