Obama, South Korea's Lee aim to impede North Korea's nuclear program

WASHINGTON (Reuters) - President Barack Obama spoke to South Korean President Lee Myung-bak on Tuesday about North Korea's "highly provocative" nuclear test and agreed to work with the United Nations Security Council to address it, the White House said in a statement.

"They agreed to work closely together, including at the United Nations Security Council, to seek a range of measures aimed at impeding North Korea's nuclear and ballistic missile programs and reducing the risk of proliferation," the White House said of the two men's discussion.

"President Obama unequivocally reaffirmed that the United States remains steadfast in its defense commitments to the Republic of Korea, including the extended deterrence offered by the U.S. nuclear umbrella," it said.

(Reporting by Jeff Mason and Tabassum Zakaria; Editing by Sandra Maler)