North Korea says it will not re-enter six-party talks to end its nuclear weapons program, citing the "deep-rooted anti-North Korean policy" of the United States.

"The six-party talks are over," Ri Hung Sik, spokesman for the North Korean delegation at a major Asian security conference, said Thursday.

North Korea's six-party negotiations — with the U.S., Russia, China, Japan and South Korea — ended last year after Pyongyang went back on a promise to halt its nuclear program.

U.S. Secretary of State Hillary Rodham Clinton urged Asian nations to vigorously enforce the latest U.N. sanctions against North Korea. She said Washington would pursue "every avenue" to denuclearize the Korean peninsula.