A North Korean spokesman says the U.S. should halt sanctions and military exercises with South Korea if it wants a nuclear-free peninsula.

"If the U.S. is really interested in the denuclearization of the Korean peninsula, it should halt the military exercises and sanctions that destroy the mood for dialogue," North Korean spokesman Ri Tong Il told reporters in Hanoi on Thursday.

U.S. Secretary of State Hillary Clinton announced Wednesday the U.S. would impose new sanctions on the reclusive North four months after the sinking of a South Korean warship that killed 46 sailors and has been blamed on Pyongyang. The North has denied involvement.

The allies announced they would hold four days of joint military exercises starting Sunday.