White House press briefing Tuesday, March 13

Earlier Tuesday President Obama took a moment to address concerns over the shooting of Afghan civilians over the weekend, prior to his public remarks on new China trade enforcement measures.

"The Unites States takes this as seriously as if it was our own citizens, our own children. We're heartbroken over the loss of innocent life," he said Tuesday in the Rose Garden at the White House. "It's not who we are as a country and it does not represent our military."

He told the audience that he has directed the Pentagon to "spare no effort" in the investigation into the killings.

Obama was announcing the administration's effort to step up pressure on China to loosen export restrictions on rare-earth materials that are central to producing high-tech products and important to a broad range of U.S. businesses.  

The U.S. — along with the European Union and Japan — filed a case with the World Trade Organization (WTO) on Tuesday requesting talks with China over its export controls.

Also Tuesday, Obama will meets with the 2012 Intel Talent Science Talent Search finalists and later travels with Great Britain's David Cameron to Dayton, Ohio as part of the prime minister's official visit to the United States.

The president and the prime minister are headed to the The Buckeye state to attend the first round game of the NCAA men's basketball championship. The White House hosts a state dinner for Cameron Wednesday night.

Obama and Cameron touted the mutual goals and shared values between their two countries in a joint op-ed in The Washington Post Tuesday, where the two world leaders aimed to showcase unity on global hotspots like Afghanistan, Syria, and Iran.

The meeting between Obama and Cameron, which was announced by the White House in early February, comes at a time when there is growing concern over relations with the Afghan government, stemming from Sunday's killing of civilians and last month's accidental burning of Qurans on a U.S. airbase.

"Our troops and citizens have long shown what can be achieved when British and Americans work together, heart and hand, and why this remains an essential relationship — to our nations and the world," wrote Obama and Cameron in the article.

—This event has concluded and has been updated to include the complete press conference.