South Korean President Park Geun-hye spoke with U.S. President Barack Obama and Japanese Prime Minister Shinzo Abe on Tuesday, agreeing to work for "strong and effective" U.N. sanctions against North Korea following its weekend rocket launch.
North Korea says it put a satellite into orbit on Sunday, but the United States and its allies see the launch as cover for Pyongyang's development of ballistic missile technology that could be used to deliver a nuclear weapon across the Pacific Ocean.
In a telephone conversation on Tuesday, Park and Obama agreed various sanctions outside the U.N. were also needed to punish North Korea, Park's office said in a statement.
"The two leaders agreed for the two countries to cooperate closely for the adoption of strong and effective sanctions resolutions as a united response by the international community against the North's nuclear test and a rocket launch using ballistic missile technology," the presidential Blue House said.
The U.N. Security Council on Sunday strongly condemned North Korea's rocket launch and promised to take action, while Washington vowed to ensure the 15-nation body imposed "serious consequences" on Pyongyang as soon as possible.
However, China, North Korea's key ally and a veto-wielding member of the United Nations Security Council, has resisted harsh sanctions sought by the United States and South Korea following the North's Jan. 6 test of a nuclear device Pyongyang claimed is a hydrogen bomb.
A senior U.S. official said on Monday that China agrees any new U.N. resolution on North Korea will include additional sanctions and go beyond previous steps, but Washington is urging Beijing to put even more pressure on Pyongyang.
China is in "unique position" as North Korea's neighbour and ally to compel it to abandon its nuclear weapons and ballistic missile programs, the official told Reuters.
"It's clear to me that our Chinese friends have indicated that the U.N. Security Council's response will include sanctions and does need to go beyond previous resolutions," he said.
"The key of course is what exactly are the specific actions that we are going to take together and that's the focus of our efforts right now," the official said. "We have made clear that China can do more and needs to do more."
Proposed sanctions have not been made public, but one diplomat told Reuters that Washington was hoping to tighten international restrictions on North Korea's banking system. Beijing was reluctant to support that step for fear of worsening conditions in its impoverished neighbour, the diplomat said.
This week, the top U.S. military commander will discuss North Korea's latest satellite launch with his Japanese and South Korean counterparts as part of efforts to strengthen military ties between the three countries, U.S. defense officials said on Monday.
The United States and South Korea announced after the missile test they had begun formal discussions about the possibility of deploying an advanced missile defense system to which China has objected, arguing it could undermine its strategic deterrent.