McCain raised $11.2 million in the second quarter.

WASHINGTON (CNN) — Sen. John McCain's presidential campaign announced staff cuts Monday after a decline in its quarterly fund-raising, a slide advisers blamed on the Arizona Republican's support of a failed immigration bill.

McCain's 2008 effort took in $11.2 million between April and June, down from the $13 million raised in the first quarter of 2007, the campaign announced. His first-quarter receipts trailed two other GOP contenders, former Massachusetts Gov. Mitt Romney and former New York City Mayor Rudy Giuliani.

Romney and Giuliani have yet to announce their totals for the second quarter, which ended Saturday. Candidates have until July 15 to file quarterly reports with the Federal Election Commission.

In a conference call with reporters Monday afternoon, McCain campaign manager Terry Nelson announced a major "restructuring" of the campaign, which had $2 million remaining in the bank as of Saturday. In addition to across-the-board staff cuts, Nelson said he will work without pay for the next few months, and several other top aides will work at reduced pay.

Nevertheless, senior McCain strategist John Weaver said McCain still intends to stay in the race and win.

"In the environment we're in, the amount of money raised by this campaign and the finance team is a remarkable achievement, and to do so with a principled candidate makes us proud," Weaver said.

Nelson blamed the skid on McCain's full-throated support for a "grand bargain" to overhaul U.S. immigration laws, which would have established a guest-worker program and provided a path to legal status for an estimated 12 million-plus illegal immigrants now working in the United States.

"John McCain has fought for change throughout his entire career. He's taken principled stands that have made him a courageous leader and courageous presidential candidate," Nelson said. "And these things will make him a remarkably effective president, but it sometimes makes fund-raising more challenging."

At a June 5 debate among GOP candidates, McCain was a lonely voice in support of the White House-backed bill. The measure failed in the Senate on Thursday amid intense opposition from much of the GOP base, who derided it as "amnesty" for illegal immigrants.

A CNN/Opinion Research Corporation poll in late June showed that 52 percent of Republicans opposed the plan, and two out of three said immigration will be extremely or very important to their vote in 2008.

Nelson said McCain's stand demonstrated his adherence to principle, and called it "the right decision for our country." But he said the campaign is scaling back "incorrect" early assumptions that it would raise $100 million in 2007, and would consider taking public funds for the GOP primary race.

"The decisions we made today were not easy. They were tough decisions," he said. "But these decisions will make John McCain the nominee of the Republican Party."

– CNN's Robert Yoon contributed to this report