WASHINGTON (AP) — House Republicans rebuffed their Senate counterparts Monday over must-pass highway legislation, setting the two chambers on a collision course days ahead of a crucial deadline in the midst of the summer driving season.

As House members convened for their final days of work before an annual August recess, Majority Leader Kevin McCarthy ruled out taking up the Senate's highway bill, which is headed for completion in the next several days.

"We're not taking up the Senate bill," the California Republican told reporters at the Capitol, adding that the Senate should instead take up the bill already passed by the House. "My best advice to the Senate is to get our highway bill moved forward," he said.

The House bill is a five-month extension of current programs while the Senate's version authorizes $350 billion in transportation programs for six years, though only three of those are paid for.

Authority for federal highway aid payments to states will expire Friday at midnight without action. At the same time, if Congress doesn't act before then the balance in the federal Highway Trust Fund is forecast to drop below a minimum cushion of $4 billion that's necessary to keep aid flowing smoothly to states.

House Republican leaders say their approach would buy them time to try to come up with a tax reform deal coveted by the White House and some leaders in both parties, and use that to pay for an even longer-term highway bill. But Senate Majority Leader Mitch McConnell has said publicly and privately that such a deal will be all but impossible to achieve. He wants to move legislation now to dispense with the highway issue at least through next year's elections, give certainty to states and avoid repeated fights over the issue.

"Time is running out to get this bill through Congress. We're up against a deadline at the end of week," McConnell, R-Ky., said on the Senate floor. "Jobs are on the line. Important infrastructure projects are too. So we have to get the job done."

Despite the dispute between the two chambers there's little expectation Congress would let the Friday deadline come and go without action, given from state and local transportation agencies, the construction industry and others. But how the issue will get resolved before then is unclear. One possibility is an even shorter-term extension of two months or so, which McCarthy was careful not to rule out.

Already the highway bill has become the vehicle for troublesome political fights over other issues, including the federal Export-Import Bank, a little-known lending agency that's hotly opposed by conservatives and was allowed to expire June 30. The Senate was expected to vote later Monday to add legislation reviving the bank to the highway bill, despite furious opposition from presidential candidate Sen. Ted Cruz, R-Texas, who accused McConnell of lying to him over the issue.

Cruz's accusations brought an extraordinary rebuke Sunday from leading Senate Republicans, who took to the Senate floor to call for civility and dispute his claims. And more Republican infighting broke out Monday, as an email surfaced from an aide to Sen. Mike Lee, R-Utah, suggesting that conservative groups should take Lee's fellow Republicans to task if they oppose him on a legislative maneuver to advance a repeal of President Barack Obama's health care law.

The move angered Republicans and was expected to be discussed at a closed-door meeting of senators Monday night. Lee's office quickly sought to contain the damage. A statement from communications director Conn Carroll said Lee had personally apologized to McConnell as soon as he found out about the email. "This email is not how Sen. Lee does business," Carroll said.

If the House does leave Washington Thursday without taking up the Senate's highway bill, that would mean the Export-Import Bank stays dead, at least until the fall, because the House version of the bill does not include it.

But McConnell is just as reluctant to take up the House's highway legislation, and the authors of the Senate's version took to the Senate floor Monday to urge McCarthy and House members to relent and act on the Senate version.

"I still am thinking that brighter minds will prevail," said Sen. James Inhofe, R-Okla.

Sen. Barbara Boxer, D-Calif., who has bucked many in her party by collaborating with Inhofe and Republican leaders on the bill, urged the House to postpone its recess and take up the Senate bill. "I know you want to get out of town, everybody does, it's August and we have plans," she said. "But you know what, we're staying an extra week in August, you can stay an extra week in August. That's not such a terrible thing."

McCarthy did not sound open to any such suggestion, flatly telling reporters, "We are set to depart on Thursday."