WASHINGTON, Aug 25 (Reuters) - Former U.S. Vice President Dick Cheney criticized President Barack Obama's ability to handle national security after the Justice Department appointed a special prosecutor to investigate CIA interrogation abuses.

Cheney, who has emerged as a vocal defender of Bush administration policies since leaving the White House, said the intelligence obtained from harsh interrogation techniques had saved lives.

"The people involved deserve our gratitude. They do not deserve to be the targets of political investigations or prosecutions," he said in a statement dated Monday.

Cheney took issue with the Obama administration's decisions this week to have a special prosecutor investigate CIA prisoner abuse cases and to have a new group handling terrorism interrogations report to the White House.

"President Obama's decision to allow the Justice Department to investigate and possibly prosecute CIA personnel, and his decision to remove authority for interrogation from the CIA to the White House, serves as a reminder, if any were needed, of why so many Americans have doubts about this Administration's ability to be responsible for our nation's security," Cheney said.

Earlier this year, Cheney had asked the CIA to declassify two memos that he said showed the effectiveness of using harsh interrogation methods on terrorism suspects.

The CIA in May rejected that request, but on Monday released the documents, with classified portions blacked out.

"The activities of the CIA in carrying out the policies of the Bush Administration were directly responsible for defeating all efforts by al Qaeda to launch further mass casualty attacks against the United States," Cheney said. (Reporting by Tabassum Zakaria; editing by Mohammad Zargham)