WASHINGTON — Lawmakers said they reached an election-year deal keeping interest rates from doubling on millions of student loans, and were nearly there on a bill securing long-term funding for US roads, bridges and railways.

Student loan rates are set to double after Saturday, from 3.4 to 6.8 percent, if Congress does not pass an extension of the reduced interest rates, while lawmakers stress that 1.9 million jobs are in the balance with the passage of a massive but long-stalled transportation bill.

President Barack Obama has used the months of debate over student loans as a campaign issue to rally young voters as he seeks re-election against Republican rival Mitt Romney in November.

"We're pleased that the Senate has reached a deal to keep rates low and continue offering hard-working students a fair shot at an affordable education," the White House said in a statement Tuesday.

"We hope that Congress will complete the legislative process and send a bill to the President as soon as possible."

Senate Majority Leader Harry Reid said he was buoyed by progress achieved during marathon inter-party negotiations.

"We're very close to having everything done," Reid said of the so-called highway bill.

But he still warned things could fall apart if the bill doesn't come together by Wednesday, to allow for congressional procedure that would see the legislation pass both chambers of Congress and reach Obama's desk for his signature by the end of the month.

"I'm convinced that when this is all over with, we could have a very, very good highway bill that would include transit and would include some things that we work with here in the Senate," Reid told reporters.

A two-year, $109 billion transport plan passed the US Senate in March but stalled in the House of Representatives, where it faced opposition from conservative Republicans who want to cut government spending.

Lawmakers have yet to say whether the final negotiated deal will include construction of the controversial Keystone XL oil pipeline, which has been strongly pushed by Republicans.

Reid and Republican Minority Leader Mitch McConnell said the parties have agreed on the student loan rate extension, but there was still a question as to how it could get through Congress before Sunday.

"Senator Reid and I have an understanding that we think will be acceptable to the House," McConnell told reporters.

"That may or may not be coupled with the highway proposal," he added, explaining that both pieces of legislation could be lumped together.

Both leaders say they don't want to see the student loan rates go up; the question has been how to pay for the extension of the low rates.