U.S. President Barack Obama said on Friday that capturing terror mastermind Osama bin Laden is still extremely important to national security, although it won't "solve all the problems."

Nine years after masterminding the 9/11 attacks and evading the U.S. forces, the al-Qaeda leader has "gone deep underground," but the United State will continue to hunt him, said Obama.

Obama said it remains a high priority to capture or kill bin Laden, and the country's best intelligence officers and special forces are working night and day to make that happen.

As the country gets ready to commemorate on Saturday the deadly attacks on American soil that took thousands of lives on Sept. 11, 2001, Obama said al-Qaeda is holed up under U.S. pressure, and it is difficult for the group to operate.

Obama made the remarks during a news conference in the White House. He said extremist groups such as al-Qaeda are still the country's most dangerous enemies.

Reflecting on the war on terror, Obama expressed regret over the failure to close the Guantanamo Bay prison facility, which he said has been, and still is being, used by al-Qaeda for recruitment purposes.

"One where we've fallen short is closing Guantanamo. I wanted to close it sooner. We have missed that deadline. It's not for lack of trying. It's because the politics of it are difficult," said the president.

Obama promised to close the infamous facility in one year after he took office, but the facility still holds over 100 prisoners today.