(Image Credit: Joshua Roberts/Bloomberg via Getty Images)

President Obama today emphasized that recent difficulties in the Afghanistan war would not result in a speedier withdrawal of U.S. troops.

"In terms of pace, I don't anticipate at this stage that we're going to be making any sudden additional changes to the plan that we currently have," the president said at a joint appearance in the White House Rose Garden with British Prime Minister David Cameron .

Noting that 10,000 U.S. troop have already left Afghanistan in the last year, with an additional 23,000 scheduled to withdraw by this summer, the president insisted that "a robust Coalition presence" would remain in the country during the Summer fighting season "to make sure that the Taliban understand that they're not going to be able to regain momentum. After the fighting season, in conjunction with all our allies, we will continue to look at how do we effectuate this transition in a way that doesn't result in a steep cliff at the end of the 2014 but rather is a gradual pace that accommodates the developing capacities of the Afghan national security forces."

The two men today agreed to stick with "the transition plan that we agreed to with our coalition partners in Lisbon," President Obama said. At the upcoming NATO summit in Chicago in May, they will announce the speed at which the U.S. will shift to a support role in 2013.

"This is a hard slog," the president said when asked about polls indicating the public wants the war to end. "This is hard work…Why is it that poll numbers indicate people are interested in ending the war in Afghanistan? It's because we've been there for 10 years, and people get weary. And they know friends and neighbors who have lost loved ones as a consequence of war. No one wants war. Anybody who answers a poll question about war saying enthusiastically, we want war, probably hasn't been involved in a war. "

In addition to Afghanistan, the president and prime minister told reporters that they today focused on Iran's nuclear program, Syria, and economic recovery.

"We believe there is still time and space to pursue a diplomatic solution, and we're going to keep coordinating closely with our P-5 plus one partners," the president said, referring to the six countries participating in discussions with Iran about its nuclear program: the U.S., U.K., Russia, China, France and Germany. But, he said, "the window for solving this issue diplomatically is shrinking." The president said that economic "sanctions are going to begin to bite even harder this summer. And we're seeing significant effects on the Iranian economy….Do I have a guarantee that Iran will walk through this door that we're offering them? No."

Cameron said that the "embargo is dramatically increasing the pressure on the regime" but cautioned that military action remained a possibility. "As the president and I have said, nothing is off the table."

On Syria, Cameron begged off questions about imposing a no-fly zone, saying that the U.S./U.K. focus right now is "on trying to achieve transition, not trying to foment revolution. We think that the fastest way to end the killing, which is what we all want to see, is for Assad to go." Asked if President Bashar al-Assad ought to be tried as a war criminal, Cameron broadened the question to "the issue of holding people responsible," and on that he said, "I do."

"People should always remember that international law has got a long reach and a long memory," Cameron said, "and the people who are leading Syria at the moment and committing these crimes need to know that."

Asked how he could help convince the Russians to join the international condemnation, Cameron said the appeal to Russia would need to be "to their own interests. It's not in their interest to have this bloodied, broken, brutal regime butchering people nightly on the television screens. The irony is that people in Syria often felt that the Russians were their friends and many in the West they were more suspicious of. Now they can see people in the West wanting to help them, raising their issues, calling for the world to act on their problems, and we need to make sure that Russia joins with that."

The two men also took some time to joke about their various exploits in sports, with the president having taken the prime minister to an NCAA March Madness game yesterday in Dayton, Ohio. The president recalled his 2011 visit to London when he and Cameron played ping pong against some university students. "As they would say in Britain, we got thrashed," the president said. "So when it came to sports on this visit, I thought it would be better if we just watched."

Cameron admitted that he had suspected "a link between that and the table tennis." Knowing that "America doesn't like being on the losing side, I'm trying to make up to you with the gift of a table tennis table."

"We should practice this afternoon," the president said.

"I certainly need the practice," Cameron agreed. "And one of these days I'll get my own back by getting you to a cricket match and explaining the rules to you and some of the terminology that you'll have to try and get straight, as I tried last night."

-Jake Tapper