President Obama urged Congress on Friday to pass a new student-loan bill within the next month to prevent what he said would be a doubling of rates on government-subsidized loans for the nation's college students.

Appearing in the White House Rose Garden before an audience of students, Obama said: "If Congress doesn't act by July 1, federal student loan rates are set to double." He said the average student would rack up an additional $1,000 in debt.

Obama urged students to lobby lawmakers to improve on a House bill that the White House argues does not go far enough. He said it "fails to lock in low rates for students next year" and "eliminates safeguards for low-income families."

"The House bill isn't smart, and it's not fair," Obama said. "So I'm asking young people ... to make their voices heard once again."

The exhortation marked the second year in a row that Obama has sought to negotiate an extension of the lower rates on the loans. Last year, during the presidential campaign, Congress and the White House engaged in political brinksmanship before agreeing just days before the deadline on a plan to freeze the interest rate at 3.4 percent for one year.

The rates will rise automatically to 6.8 percent, impacting some 7 million loan recipients, unless Congress passes a measure to extend the lower rates by July 1.

Separately, the Democratic Congressional Campaign Committee said Friday it would launch ads in six college newspapers to single out Republicans on the issue. The DCCC ads are slated to target GOP Reps. John Kline (Minn.), Gary G. Miller (Calif.), Jaime Herrera Beutler (Wash.), Steve Southerland (Fla.), Rodney Davis (Ill.) and Joseph J. Heck (Nev.).

White House officials said the president’s proposal, in his budget for fiscal 2014, would freeze the low rates and allow an incoming college freshman who borrows $27,000 over four years to save an average of $4,000 over the life of those loans. According to the White House, the House plan would require the student to pay $200 more than if the rates rise to 6.8 percent.

“While we welcome that House Republicans have paid some attention to this issue this year, their proposal, unfortunately, does not meet the test,” White House Press Secretary Jay Carney said.

Obama highlighted the rising costs of higher education as part of his reelection platform, appealing to young voters in campaign appearances in swing states across the country.

But Brendan Buck, spokesman for House Speaker John A. Boehner (R-Ohio), said this week that the president’s student-loan push amounted to a public relations gambit that “reeks of desperation.”

Buck said House Republicans have approved a plan to keep rates lower. He charged that the White House is using the Rose Garden event as a way to “change the subject from its growing list of scandals.” That was a reference to the administration’s handling of the terror attack on a U.S. diplomatic post in Benghazi, Libya; the Internal Revenue Service’s targeting of conservative groups; and the Justice Department’s secret seizure of reporters’ phone records in a leak investigation.

“Picking a fight out of thin air where there’s policy agreement isn’t going to get the White House out of trouble,” Buck said, “and it certainly doesn’t do anything to help students facing a looming rate hike.”

In his speech Friday, Obama said: "We cannot price the middle class ... out of a college education. We can't keep saddling young people with more and more debt just as they're starting out in life."