The leading U.S. envoy on North Korea's nuclear program is to meet with his Japanese counterpart Monday in Tokyo.
Assistant Secretary of State Christopher Hill is scheduled to talk with Kenichiro Sasae, Japan's chief delegate to the six-nation talks on dismantling Pyongyang's nuclear weapons program.
After Hill's two days of meetings, his boss, Secretary of State Condoleezza Rice, will arrive in Japan Wednesday. She and Japanese Foreign Minister Taro Aso are to travel to South Korea for three-way talks on persuading Pyongyang to return to negotiations.
The United States is urging China to fully enforce sanctions against North Korea, which the U.N. unanimously approved Saturday.
Beijing's U.N. ambassador, Wang Guangya, says China opposes a provision that requires U.N. members to search vessels and vehicles coming into or out of North Korea.
The diplomatic activity follows Pyongyang's claims of a nuclear test a week ago.
The U.N. resolution also bans Pyongyang from importing or exporting some military hardware and bans sales of luxury goods to the country.
North Korea's neighbors have welcomed the measure.
South Korea says it will "faithfully implement" the resolution. Japanese Prime Minister Shinzo Abe says Tokyo is considering imposing additional sanctions of its own.
However, the chairman of South Korean President Roh Moo-hyun's Uri party says Seoul should not participate directly in interdicting North Korean shipping, saying such action could spark an armed conflict.
Some information for this report provided by AP, AFP and Reuters.