The U.S. Department of Transportation has enough flexibility in its budget to extend its emergency funding for bridge repair in Minneapolis, the head of the Senate Transportation Appropriations Subcommittee said Thursday, but legislation must be pushed through to increase a $100 million per incident cap on emergency relief.

Sen. Patty Murray, D-Wash., sent her staff Thursday to the site of Wednesday's devastating bridge collapse along Interstate 35W in Minneapolis. The bridge dropped unexpectedly during the evening rush hour, killing at least four and injuring scores.

Back in Washington, Minnesota lawmakers scrambled to introduce legislation that would waive the cap and enable the Transportation Department to provide $250 million in federal highway relief funding.

Minnesota Sens. Norm Coleman and Amy Klobuchar said they are working with Rep. James Oberstar, chairman of the House Transportation and Infrastructure Committee, on legislation they hoped to have passed by day's end.

Speaking to reporters, Oberstar, D-Minn., leveled criticism at the Bush administration for cutting corners on the 2005 highway bill.

"We have provided in excess of $2 billion a year for bridge reconstruction, maintenance, in the current transportation law, something I insist -- we would have had more; we would have had roughly $3 billion if this administration and Bush 43 had not insisted on a $90 billion smaller transportation program," he said.

"I don't know who's going to be the (next) president, but whoever is is going to listen to the Congress, not the other way around," Oberstar said.

Democratic lawmakers also went on the attack against President Bush and his officials for not proposing enough money to pay for transportation costs. Bush has threatened to veto this fiscal year's transportation legislation, which has $1.1 billion more than last year to fund highway programs, including bridge maintenance.

"That's $631 million over the president's budget proposal. There's also $5 billion for the highway, bridge and rehabilitation program. ... So this is the kind of bill he's threatening to veto," Murray said.

Murray went on to say that the nation's Highway Fund is projected to be $4 billion in the red by the end of 2009. "We need proposals from [the White House] on how they intend to fix that," she said.

Speaking to reporters following a Cabinet meeting that focused in part on the budget and economy, President Bush promised a "robust" response to the tragedy that has claimed at least four lives and injured dozens. He turned to the appropriations bills that need to be passed by the start of the 2008 fiscal year on Oct. 1.

"By the end of this week, members are going to be leaving for their month-long August recess. And by the time they will return, there will be less than a month before the end of the fiscal year on September the 30th, and yet they haven't passed one of the 12 spending bills that they're required to pass," Bush said.

The remarks steamed Senate Democrats. The president "must be in the Twilight Zone," said Senate Majority Leader Harry Reid. "Where was he in the first half of his presidency when the Republicans weren't getting anything done?" .

Klobuchar, a Democrat, called for patience in the investigation into what caused the 40-year-old bridge to just drop out of the air, but said her first priority is to provide needed resources to rebuilding and making sure other bridges are secure.

"A bridge in America just shouldn't fall down," Klobuchar said at a news conference with Transportation Secretary Mary E. Peters and state officials in Minneapolis. "We have to get to the bottom of this.

"We are going to make sure that not only are the immediate resources there ... but for the long-term recovery," she added. "We need funding to keep our bridges strong and we need emergency funding when tragedies happen like this."

Klobuchar said congressional leaders already are figuring out what to do, but the most immediate action appears to be through Oberstar's work.

Coleman, a Republican, noted that even before the collapse he had already introduced a bill calling for better inspection of the nation's road infrastructure including bridges. That bill would establish a commission, which would report its findings in 2010.

Speaking with FOX News Thursday, Oberstar said Minnesota officials should have acted differently in response to reports in recent years that the bridge was "structurally deficient." He said the state had resources that could have been used for bridge repair — including a 46 percent increase in federal transportation funding for the state from the 2005 highway bill.

The Minnesota Department of Transportation "should have taken its own ratings seriously and either closed that bridge or much earlier begun the reconstruction," Oberstar said.

Peters told reporters in Minnesota that a "structurally deficient" rating "does not mean that the bridge is not safe to drive over." The rating is used for monitoring the bridge and for rehabilitation to take place "at some point in the future." She added that Minnesota's Department of Transportation "in no way" put people at risk by not closing down the bridge before it collapsed.

Oberstar noted that 585,000 bridges in the United States receive federal highway aid, and up to 30 percent of them are structurally deficient to some extent. He added that 70 percent of the nation's traffic travels over just 547 bridges each day.

Minnesota Gov. Tim Pawlenty told FOX News early Thursday that the state budget had not allocated money to be used for bridge repair, the bridge is frequently inspected and those reports "called for potential replacement in 2020 or so."

The inspection didn't call for "a near-term or immediate plan" to reinforce the bridge, he added.

FOX News Radio's Mike Majchrowitz contributed to this report.