During a joint news conference Wednesday, President Barack Obama and British Prime Minister David Cameron said they remain committed to the NATO withdrawal timeline for Afghanistan.
However, both American and British forces currently deployed in Afghanistan remain in danger after a mass killing allegedly perpetrated by an American soldier.
Obama said the recent events are a reminder of the importance of the difficult mission for the two countries.
"NATO forces are making "undeniable" progress in Afghanistan," Obama said during the conference held in the White House Rose Garden Wednesday afternoon. "But recent tragic events are a reminder that the mission is still difficult."
Both leaders made it clear they remain committed to the timeline that the United States, Britain, and their NATO allies have agreed to -- shifting to a support role in Afghanistan in 2013.
Obama said that the next phase in the transition will be an important step in turning security control over to the Afghans by the end of 2014.
Cameron noted the mission goals will be met by the two countries before any withdrawal begins.
"Afghanistan must never again be a point for al-Qaeda to able to launch attacks against the U.S. and Britain," he said.
On the subject of Iran, Obama said there is still "time and space" for a diplomatic solution, in lieu of a military strike to set back Iran's progress toward a possible bomb. But he said "the window for diplomacy is shrinking."
"Iran must meet obligations to international community or face the consequences," the president said.
Concerning Syria, Cameron said that his country is working with U.S. trying to get more humanitarian aid to the people who need it, but he also stressed that the "killing must stop."
When asked about possible military intervention, Obama stressed that such action would lead to even more killing and possibly a civil war.
"Assad will leave power. It's not a question of if -- but when," Obama said.
Pomp and Pageantry
Upon Cameron's arrival at the White House earlier Wedsneday, Obama declared that the bonds between American and Britain are stronger than ever.
"We believe that our citizens should be able to live free form fear," Obama told a large crowd at the White House.
"So like generations before us, we stand united in the defense of our countries and against those who would terrorize our people or endanger the globe with the world's most dangerous weapons," he said.
Cameron echoed the two countries lasting kinship and the work that must be accomplished.
"Whenever an American president and a British prime minister get together, there is a serious and important agenda to work through and today is no different. Afghanistan. Iran. The Arab Spring, the need for trade, growth, jobs and the world economy," he said.
The White House was prepared with all the pageantry of an official state visit including military bands playing the national anthems of both nations, a 19-gun salute and having senior administration officials present, including Vice President Joe Biden and Secretary of State Hillary Clinton.
During his visit, Cameron also is expected to meet with New York Mayor Michael Bloomberg and Newark, N.J., Mayor Cory Booker.