WASHINGTON (Reuters) - The United States’ focus in North Korea policy will be on diplomacy and denuclearization, the White House said on Tuesday, after North Korea issued a warning to Washington over military drills in South Korea. White House spokeswoman Jen Psaki did not comment on the North Korean statement in remarks to reporters aboard Air Force One. “Our objective is always going to be focused on diplomacy and denuclearization on North Korea,” she said.