South Korea and the United States have agreed to expand cooperation as allies in dealing with the North Korean nuclear and missile issues.

Foreign Minister Yu Myung-hwan and U.S. Secretary of State Hillary Clinton held a meeting in Washington on Saturday.

The two sides agreed to expand cooperation and exchange information on North Korea’s illicit activities in order to block the country’s financial resources in addition to the United Nations Security Council actions to punish North Korea’s recent nuclear test.

Yu said he agreed with Clinton on the need for effective measures to stop Pyongyang’s nuclear and missile developments.

He added that they exchanged information on the leadership succession in the North.

Meanwhile, the United States said it will guarantee South Korea’s defense in writing during the June 16th Korea-U.S. summit in Washington, stipulating an extended provision of the U.S. nuclear umbrella.