WASHINGTON (CNN) -- While President Obama has insisted that securing Afghanistan against a rise in terrorist groups is a top security priority, Sen. John McCain said Tuesday that the problems in that country are not as thorny as those in Iraq.
Sen. John McCain says he supports President Obama's efforts in Afghanistan.
"It's [Afghanistan's] not as tough as Iraq, and don't let anyone tell you that it is, because when we started the  surge, Iraq was virtually in a state of collapse," McCain said during a speech at The Foreign Policy Initiative.
President Obama announced a troop increase Friday of 4,000 in Afghanistan, in addition to the 17,000 previously announced. Obama said those troops will help train the Afghan army and police.
While McCain said he supports the president's efforts in Afghanistan, he would increase the Afghan army beyond the planned levels.
"I would have announced a dramatic increase in the Afghan army. I'm talking about a 200, 250 thousand-person army. It's a big country, it's a big population," he said. Watch more about Obama's plan »
McCain also said that like him, many Republicans support Obama's plan in Afghanistan, but that will probably change. "I don't think there's any doubt that in a year from now, we will be looking at a greater level of opposition to the war than we are seeing today," he said.
The Arizona senator also rejected the idea that success in Afghanistan depends on stability in Pakistan.
"This notion that you can't succeed in Afghanistan without a success in Pakistan, I don't subscribe with it. We need a strategy for both countries, but we also need a separate strategy in regards to Pakistan by itself," McCain said.
Obama has said that his administration is prepared to continually adjust its strategy in Pakistan and Afghanistan as necessary.
On Friday, Obama announced a new plan for the region calling for, among other things, more U.S. troops, greater economic assistance, improved Afghan troop training and added civilian expertise to defeat the "terrorists who planned and supported the 9/11 attacks."
"Let me be clear: Al Qaeda and its allies -- the terrorists who planned and supported the 9/11 attacks -- are in Pakistan and Afghanistan," he said Friday. "Multiple intelligence estimates have warned that al Qaeda is actively planning attacks on the U.S. homeland from its safe haven in Pakistan."
On Tuesday, McCain said that achieving victory in Afghanistan is vital to American national security.
"We will and can and must succeed, but it's not going to be easy," he said.
Those comments come just weeks after McCain insisted the U.S. is losing the war in Afghanistan.
McCain, speaking at the American Enterprise Institute in late February, said, "When you aren't winning in this kind of war, you are losing. And, in Afghanistan today, we are not winning."
But it was McCain who, during the 2008 presidential election, blasted Obama for believing the U.S. was losing the war in Afghanistan.
Shortly after Obama laid out his foreign policy vision in Washington in mid-July of 2008, McCain criticized his proposals as naive and premature.
"Sen. Obama will tell you we can't win in Afghanistan without losing in Iraq. In fact, he has it exactly backwards. It is precisely the success of the surge in Iraq that shows us the way to succeed in Afghanistan," he said. "It is by applying the tried and true principles of counter-insurgency used in the surge -- which Sen. Obama opposed -- that we will win in Afghanistan. With the right strategy and the right forces, we can succeed in both Iraq and Afghanistan.
McCain's Afghanistan proposal at the time included the addition of brigades, the launch of an integrated nationwide security plan for the civilian population, greater military engagement of Taliban forces and unity of command, a doubling of the size of the Afghan army, a boost in civilian-military engagement and the appointment of an "Afghanistan czar."
A Vietnam War veteran, former prisoner of war and longtime member of the Armed Services Committee, McCain said that while he knows Americans "are weary of war ... we must win [in Afghanistan]. The alternative is to risk that country's return to its previous function as a terrorist sanctuary, from which al Qaeda could train and plan attacks against America."
According to a CNN/Opinion Research Corp. poll conducted in February, two-thirds of Americans overall oppose the war in Iraq, but 64 percent of Democrats oppose the war in Afghanistan.
Bill Schneider, CNN senior political analyst, says that Americans are wary about Afghanistan because of the recession, Iraq war fatigue and frustration. Watch CNN's Bill Schneider analyze the poll »
According to the poll, only 31 percent of Americans believe the United States is winning the war in Afghanistan, and 50 percent believe the United States is winning in Iraq, the highest number in at least five years.
The poll surveyed 1,046 adult Americans by telephone February 18-19. The sampling error is plus or minus 3 percentage points.
CNN's Greg Clary and Bill Schneider contributed to this report.