A Senate Republican, angered by what he contended was Democratic footdragging, said Thursday he would block extension of the highway spending program (search), a move that on Saturday would trigger the shutdown of federal funding to the states and result in thousands of layoffs.

"I'm taking this radical step because the people of America need to know," said Sen. Kit Bond (search), R-Mo., chairman of the Senate Environment and Public Works panel on transportation.

Bond was objecting to Democratic resistance to naming Senate negotiators for House-Senate talks to work out a compromise on a huge highway and transit spending bill to cover the next six years. Senate Democratic leader Tom Daschle of South Dakota has said he wants assurances that the minority Democrats will not be excluded from the negotiating process.

The political squabble in the Senate came as Republican leaders and White House officials tried to break an impasse dating back to last summer over the size of the new highway bill.

Senate Democratic Whip Harry Reid (search) of Nevada warned that if Bond continues to block a proposed two-month extension of the old program to keep projects moving until a new bill can be passed, 5,000 people would be furloughed beginning Saturday, when the current extension expires.

Without the extension, four Transportation Department agencies — the Federal Highway Administration, Federal Transit Administration (search), National Highway Traffic Safety Administration and Federal Motor Carrier Safety Administration (search) — would have to close.

The House on Wednesday approved the two-month extension on a 410-0 vote.

Reid said Bond was "shooting himself in the foot by not agreeing" to the extension.

House Speaker Dennis Hastert, R-Ill., and Senate Majority Leader Bill Frist, R-Tenn., were meeting Thursday with White House Chief of Staff Andrew Card in search of an acceptable level of spending for the 2004-2009 bill, which is expected to create hundreds of thousands of jobs and provide a nationwide economic boost.

The administration has threatened a presidential veto of bills passed by both the House and Senate, arguing that they are not fiscally responsible in a period of mounting budget deficits.

The Senate approved a $318 billion bill for the 2004-2009 period. Hastert, trying to avoid what would be the first veto of the Bush presidency, trimmed the House bill down to $275 billion. But the White House, saying the real cost of the House bill was $284 billion, rejected it and declared that the ceiling should be $256 billion.

The 1998-2003 highway bill, providing $218 billion for highways, mass transit and safety programs, expired last September. Congress has twice before extended it to keep federal funds flowing to the states.

House Majority Leader Tom DeLay, R-Texas, said Wednesday that the purpose of Thursday's Republicans-only meeting was to reach a general understanding with the White House over the size of the bill before formal congressional negotiations on the details begin.

"There has been confusion as to what the president will or will not accept," he said in a House floor dialogue with House Democratic Whip Steny Hoyer of Maryland.

Hoyer noted that more than two-thirds of House members voted for the $275 billion bill and there was "very strong sentiment that this bill is at the appropriate level."

On the Senate side, 20 Republicans, led by Sens. Mike Crapo, R-Idaho and Jim Talent, R-Mo., sent Frist a letter saying that anything less than the $318 billion approved by the Senate "would be a step backward that our nation cannot afford to take."

Once an agreement is reached with the White House, negotiators would still have to work out sensitive questions of how federal funding is distributed among the states.

Federal highway funds are derived from the federal gas tax of 18.4 cents a gallon that drivers pay at the gas pump. States that pay more into the Federal Highway Trust Fund (search) than they get back have long complained about the distribution formula. There also has been criticism of the growing number of "earmarks" — more than 3,000 in the House bill — that direct projects to individual lawmakers' districts and are generally not covered by the formula.