The U.S. is vowing to thwart North Korea’s ambitions to produce and possess nuclear weapons.

U.S. Undersecretary of State for Arms Control and International Security Ellen Tauscher told foreign correspondents in Washington that there are no reasons for North Korea to have nuclear weapons.

She said that in cooperation with allies, the U.S. will continue to pressure North Korea to give up its nuclear ambitions.

Tauscher said the U.S. supports a nuclear-free Korean Peninsula and is working hard for the resumption of the six-way nuclear talks. She urged North Korea to take transparent and open actions and end its provocations.

She said Washington is also seeking to strengthen the Nuclear Nonproliferation Treaty in a meeting on the review of the nuclear treaty in May in New York.

Tauscher reiterated that the U.S. will not allow South Korea to conduct "pyroprocessing” spent fuel treatment through a revision of a South Korea-U.S. atomic accord.