U.S. troops will take greater risks to fight the Islamic State on the ground in Iraq and Syria, Defense Secretary Ash Carter said Tuesday as he unveiled a tougher approach toward the extremist group aimed at breaking a months-long stalemate.

Carter outlined the new approach to the Senate Armed Services Committee that appeared to take committee members by surprise. Chairman John McCain, who had called Tuesday's hearing amid Republican frustrations at what they see as a too-passive approach to fighting the Islamic State by the Obama administration, admonished him and Joint Chiefs Chairman Gen. Joe Dunford that their written testimony should have been submitted 24 hours in advance.

The new approach relies on boosting support for Iraqi forces seeking to push back the Islamic State in Ramadi, and for Syrian rebels approaching the extremist group's headquarters at Raqqa. A third peg, which Carter foreshadowed Friday in a briefing for Pentagon reporters, will be stepped-up raids by U.S. special operations forces against targets of opportunity such as the one last week on a prison in northern Iraq in which a U.S. soldier was killed.

"Our strategy's execution can and must and will be strengthened," Carter told the panel.

The new approach was the result of a Pentagon review of its efforts over the past several weeks, said Dunford, a Marine who took over from Army Gen. Martin Dempsey at the end of September.

"No one is satisfied with our progress to date," Dunford said. "We're not satisfied or complacent about where we are and we won't be satisfied until ISIL is defeated."

The Pentagon, however, was not prepared to embrace the idea of a "safe zone" for civilians inside Syria that has gained bipartisan support among lawmakers as hundreds of thousands of refugees inundate European countries, with Carter saying options for doing so are "complex and raise some challenges."

He told lawmakers the Pentagon was not yet prepared to recommend the idea, but the White House has not taken it off the table.

The beefed-up approach didn't appear to be enough for McCain, who rejected "policies of gradual escalation." The Arizona Republican has been one of the harshest critics of President Obama's strategy, particularly in Syria, where he wants U.S. forces also to target President Bashar al-Assad.

"A policy of 'ISIL first' fails to understand that ISIL, for all of the threat it poses, is actually just a symptom of a deeper problem — the struggle for power and sectarian identity now raging across the Middle East, the epicenter of which is Iraq and Syria," McCain said, using the government's acronym for the Islamic State. "That is why ISIL exists today with the strength that it does, and this problem will only get worse the longer this conflict rages on."

Much of the recent criticism has centered on Obama's refusal to adjust U.S. efforts in the face of Russian military intervention in Syria. Though attacks by Russian forces have targeted rebels supported by members of the U.S.-led coalition and forced U.S. aircraft attacking the Islamic State to change their flight paths, the White House has chosen only to chastise Russian President Vladimir Putin for his strategic "mistake," and is focused on trying to persuade the Kremlin to help peacefully ease Assad out of power.

The new approach does not change administration policy that Assad's regime should be dealt with by diplomatic means.

"The decision has been made that the issue of Assad is being solved politically right now," Dunford said.

McCain already had signaled his opposition to that decision before the two Pentagon officials spoke.

"We hear it said all the time that there is no military solution to this problem, which is a truism. But that, too, is misleading. The real problem is that there can be no diplomatic solution without leverage, and there is a clear military dimension to this problem," he said in his opening statement.

"Secretary [of State John] Kerry can take all the trips he wants to Geneva, but unless the military balance of power changes on the ground, diplomacy will achieve nothing."