President Obama said it is time for the United States to "start going on some offense" to stop the advances of the Islamic State in the Middle East as he prepared to announce the next phase of the U.S. effort that he said would require additional resources in the region.

"There's going to be a military element to it," Obama said in an interview to air Sunday on NBC's "Meet the Press." "And what I want people to understand, though, is that over the course of months, we are going to be able to not just blunt the momentum of ISIL.  We are going to systematically degrade their capabilities.  We're going to shrink the territory that they control.  And ultimately we're going to defeat them."

In a wide-ranging interview with moderator Chuck Todd, Obama also signaled for the first time he is likely to dispatch military resources to help deal with an serious outbreak of Ebola in several African countries. That comes in the wake of his administration's request of Congress last week of $58 million to help deal with that medical crisis, which Obama emphasized was not a threat to the United States.

Obama's remarks on the security situation in the Middle East came as the U.S. military launched a series of new airstrikes late Saturday against the Islamic State, also known by the abbreviation ISIL, which had been threatening to seize control of a second giant dam that generates electricity and irrigation for much of the country. In the "Meet the Press" interview, which was conducted Saturday at the White House, the president did not specify what stepped-up military efforts he had authorized, but he emphasized, as he has repeatedly, that it would not include commitments of large numbers of U.S. combat troops on the ground.

"This is not the equivalent of the Iraq war," Obama said. "What this is is similar to the kinds of counterterrorism campaigns that we've been engaging in consistently over the last five, six, seven years. ... We're not looking at sending in 100,000 American troops."

The interview marked the start of a concerted effort by the White House this week to more clearly enunciate the administration's strategy to deal with the Islamic State, which has shown sophisticated military capabilities and employed extreme acts of brutality, including the beheading of two U.S. journalists, in gaining wide swaths of territory in Syria and Iraq. Obama was criticized by members of Congress for saying two weeks ago that "we don't have a strategy yet" for increased action.

Obama is set to meet with the bipartisan leaders of Congress at the White House on Tuesday to discuss his plans, and he will deliver a speech to the public on Wednesday -- a day before the 13th anniversary of the Sept. 11, 2011, attacks.

"They're not a JV team," Obama acknowledged of the Islamic State, after Todd reminded the president that he had referred to offshoots of al-Qaeda as akin to junior varsity terrorist groups in an interview with the New Yorker last January. Obama told Todd he had been referring to other groups, and said the Islamic State "has metastasized, has grown.  And now we're going to have to deal."

On CNN's "State of the Union," Sen. Dianne Feinstein (D-Calif.), who had criticized Obama's approach to the Islamic State as too cautious, said: “I want to congratulate the president. He is now on the offense. He has put together the coalition of nine nations. His people are in different regional countries as we speak, consulting and trying to bring in other countries in the region. I think that this is a major change in how ISIS is approached. It is overdue, by the president is now there.”

Obama, who has called on Sunni countries in the region to help mount the military and political response to the Islamic State, did not say whether he would authorize military action in Syria, which is the militant group's home base. Instead, he said the primary fighting forces in both Syria and Iraq would have to be local troops from those countries; in Syria, where the Obama administration has called for the resignation of President Bashar al-Assad, the president suggested the U.S. would devote additional resources to moderate rebel forces, including the Free Syrian Army. Obama has previously been reluctant to bolster rebel forces because of the uncertainty over the aims of the many factions involved in that country's civil war.

The president said that Congress would be kept abreast of his decisions and that he would seek support for stepped-up U.S. efforts in the region.

"I do think it's important for Congress to understand what the plan is, to have buy in, to debate it," Obama said. The speech on Wednesday "will allow Congress, I think, to understand very clearly and very specifically what it is that we are doing but also what we're not doing."

Obama said he had seen messages delivered to him from Islamic State fighters in videos that showed the beheadings of the two American journalists -- James Foley and Steven Sotloff. The militant group has a sophisticated recruiting campaign to gain members, Obama said, and effectively employed social media to reach well beyond the Middle East. Other Sunni nations must develop an "effective counter-narrative" to explain that the Islamic State does not stand for Islam, he added.

"It is an abortion, a distortion, an abomination that has somehow tied Islam to the kind of nihilistic thinking that any civilized nation should eliminate," Obama said.

Todd also asked Obama about the U.S. role in containing the Ebola outbreak in several African nations. The president emphasized that Americans should not be concerned about contracting the disease in the United States, but he said his administration would lead the international effort to help deal with the spread of the disease.

"We're going to have to get U.S. military assets just to set up ... isolation units and equipment there, to provide security for public health workers surging from around the world," the president said. "If we do that, then it's still going to be months before this problem is controllable in Africa. But it shouldn't reach our shores."

Obama’s response comes after the medical group Doctors Without Borders, which has been one of the most active aid groups since early in the epidemic, called last week for the first time for countries to deploy “military assets.” The group has long opposed military involvement in global health crises, but is calling for it now because the world is losing the battle to contain the epidemic.

“We are asking for action now because we are going to be facing a mass casualty environment,” said Joanne Liu, the group’s international president, in an interview Friday. Every morning, on the doorsteps of the group’s Ebola treatment center in Monrovia, the Liberian capital, at least 10 patients have died on the doorsteps, she said.

“Because the response has been so slow, we now have to switch to a mass casualty response," Liu said. "Who can deploy a lot of people, with a good chain of command and discipline?”

Lena Sun contributed to this report.