'Al Qaeda leadership hunkered down in Af-Pak border region'

"Today, al Qaeda's senior leadership is under more pressure than ever before and is hunkered down in the border region of Afghanistan and Pakistan," Obama said in a statement issued on the occasion of the first anniversary of the killing of the CIA officials in Afghanistan.

"We are relentlessly pursuing our mission to disrupt, dismantle, and ultimately defeat that terrorist organisation. In the US and around the world, plots have been thwarted, attacks have been disrupted, and the lives of Americans have been saved," Obama said.

"One year ago today, at a remote outpost at Khost, Afghanistan, seven American patriots showed us the true meaning of honour, integrity, and selfless sacrifice."

For their colleagues and friends at the CIA, it was a heartbreaking loss of experienced veterans and young officers who served on the front lines in the fight to keep our nation safe, he said.

"For Americans to whom the work of our intelligence community is largely unknown, it was a rare glimpse into the risks that our intelligence professionals accept in defense of the security and freedoms that we cherish," Obama said.

"For those of us who gathered at Langley last February to pay tribute to these seven heroes and to comfort their families, it was an occasion to rededicate ourselves to their work and to the ideals for which they died," he said.

"As President, I rely on our intelligence, military, and civilian personnel every day, and I know that our country is more secure, and the American people are safer, because of their extraordinary service," he said.

"This is the legacy of the courageous Americans who gave their lives one year ago and whose stars now grace the Memorial Wall at Langley, just as it is the legacy of our troops who have given their lives in Afghanistan and Iraq. As we mark the first anniversary of their sacrifice at Khost, this is the work to which we recommit ourselves today."

"We will ensure that our dedicated intelligence professionals have the training and tools they need to meet the missions we ask of them. We will do everything in our power to ensure the safety and security of the American people.

"And like our seven patriots at Khost, we will never waver in defense of the security and liberties that keep America strong and free," Obama said.