US experts met with officials from North Korea for informal talks in London on Wednesday over the resumption of stalled international discussions on Pyongyang\'s nuclear program. Pyongyang withdrew from international talks on their nuclear program in 2009. The meeting comes just hours after the United States and South Korea signed an agreement meant to provide greater deterrence against North Korea\'s nuclear weapons, according to Voice of America (VOA). US Defence Secretary Chuck Hagel and his South Korean counterpart Kim Kwan-jin signed the deal in Seoul during annual security talks. Hagel said the plan underscores the countries\' concern over the North\'s \"nuclear and ballistic missile programs, its proliferation activities, and its chemical weapons.\" \"Today we signed a bilateral strategy for tailored deterrence against the threat of North Korean nuclear weapons and other weapons of mass destruction,\" Hagel said.