WASHINGTON (AP) — Congress ran full-tilt into election-year gridlock over immigration Thursday and staggered toward a five-week summer break with no agreement in sight on legislation to cope with the influx of young immigrants flocking illegally to the United States.

Prospects were considerably brighter for bipartisan measures to improve veterans' health care, prevent a cutoff in highway construction aid and send Israel additional money for its missile defense system. Officials in both parties said all three bills appeared likely to clear Congress by day's end and go to the White House for President Barack Obama's signature.

But three months before midterm elections, the unbreakable dispute over immigration exposed longstanding differences inside Republican ranks, postponing the start of the House's vacation one day until Friday. And a new outburst of harsh partisan rhetoric between leading officials in both parties served as yet another reminder that after 18 months in office, the current Congress has little to show for its efforts apart from abysmally low public approval ratings.

House Speaker John Boehner accused Democrats of pursuing a "nutso scheme" of trying to seize on the border crisis to try and grant a path to citizenship to millions of immigrants living in the country illegally.

Despite the attack on Democrats, it was Republican unity that cracked first.

A few hours after Boehner spoke, Republicans abruptly canceled a vote on their own border security legislation, a $659 million measure that also would make it easier to deport the children from Central America now flooding into the United States. They did so after a revolt by tea party-aligned GOP lawmakers, some of whom had conferred with Texas Sen. Ted Cruz the night before.

They argued that the leadership's offer of a vote on a companion bill, even if the legislation were approved, would fall short of reversing a 2012 administration policy under which 500,000 immigrants living in the country illegally have obtained work permits.

So chaotic was the day that after initially announcing the House had taken its last vote, Republicans abruptly reversed course and announced plans to reconvene on Friday for a possible vote on legislation related to border security and immigration — details yet to be determined.

Asked what would change overnight, Rep. Spencer Bachus of Alabama said of fellow Republicans: "I'm hoping some people will grow up."

Whatever the eventual outcome in the House, there was no talk of an attempt to forge a compromise with a far different approach developed by Senate Democrats before lawmakers left town.

The outlook was better for a $16.3 billion bill responding to a Department of Veterans Affairs scandal in which patients were shown to be subjected to extremely long delays in care while agency officials covered up the facts.

The House approved the measure on a vote of 420-5 on Wednesday, and support appeared strong in the Senate.

Most of the money will be used to let veterans seek care from outside physicians if they live more than 40 miles from a VA facility or face a long wait to see a doctor at one. The legislation also would allow the hiring of additional physicians for the VA and permit the firing of senior executives guilty of poor performance.

The bill marked a traditional compromise between the parties and the houses of the sort that lawmakers have struck for generations. Democrats gave up their insistence on more funding, and Republicans agreed to let deficits rise by $10 billion as part of the agreement rather than seek offsetting cuts elsewhere.

More urgent was the bill to prevent a reduction in federal highway construction funding at the height of the summer construction season.

The Transportation Department set Friday as the date the Highway Trust Fund will no longer be able to provide all the aid promised, and estimated that states could expect an average reduction of 28 percent unless Congress acted by then.

The two houses have played legislative ping pong with the issue in recent days. But with time running out, the Senate was expected to pass a House-approved measure making $10.8 billion available, enough to last until next May.

Legislation providing money for Iron Dome, the Israeli missile defense system, had yet to be made public late in the day. Instead, the funding was tucked inside a border security bill that was drafted by Senate Democrats and opposed by Republicans.

Officials said they expected that the Israeli money eventually would be broken out, the Senate would approve it and the House would agree.

But first, there was bickering aplenty over immigration, an issue that has divided Congress for years.

Like Boehner, Senate Republican Leader Mitch McConnell of Kentucky criticized Obama.

"It boggles the mind that the president of the United States would rather fundraise in Hollywood than ... to do something to prevent more young people from making the perilous and potentially life-threatening journey across the desert," he said.

But Rep. Nancy Pelosi, the House Democratic leader, was no more charitable about House Republicans. Referring to their leadership's maneuvers to pass their own border legislation, she said their approach would "intensify the harm for children."

The White House added its own criticism, assailing House Republicans for their inaction on comprehensive immigration legislation and accusing them of targeting a program that "has benefited more than 500,000 young people who are Americans in every way except on paper."

Administration officials have signaled that Obama intends to use an executive order to expand the program, which the president unveiled in the heat of his presidential re-election campaign in 2012.

One day after the House voted to sue the president over his enforcement of the health care law, Boehner warned him not to try freelancing on immigration.

If he does, "he'll be sealing the deal on his legacy of lawlessness," Boehner added.

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Associated Press writers Erica Werner, Joan Lowy, Donna Cassata, Andrew Taylor and Alan Fram contributed to this report.