Pressuring North Korea with sanctions will be the No. 1 topic for a trilateral summit that U.S.

President Barack Obama is scheduled to hold with South Korean President Park Geun-hye and Japanese Prime Minister Shinzo Abe this week, a top American diplomat said Tuesday.

The three leaders are scheduled to hold the three-way meeting Thursday on the sidelines of the Nuclear Security Summit in Washington. The meeting comes as Pyongyang has been ratcheting up tensions with threats of attacks, claims of breakthroughs in its nuclear and missile programs, and a series of missile tests.

"In the trilateral meeting that President Obama will have with President Park and Prime Minister Abe, I think the question of North Korea will be front and center," Deputy Secretary of State Tony Blinken said during a discussion at the Brookings Institution.

"They will focus, in particular, on implementing the UN Security Council resolution, but they'll also be discussing any additional measures that we can take either individually, or collectively, or with other countries to, again, sharpen the choice for the regime in Pyongyang. So, that will be, I think, the No. 1 topic of discussion," he said.

Blinken stressed the importance of "real pressure" on the North and urged Chinese cooperation.

"Unfortunately, the most effective way to achieve that, because all other ways seem to so far have failed, is to exert real pressure on North Korea and to force it to make a choice," he said. "A choice between continuing these actions, or choosing a course that allows it to actually provide for its own people and develop economically. It can't have it both ways, as much as it would like to."

China should work with Washington and use its influence and leverage over Pyongyang, he said, adding that Beijing has a "unique relationship" with the North.

Otherwise, Blinken said that China should put up with the U.S.

taking steps to assure its own security, as well as security of its partners and allies, such as the potential deployment of the Terminal High Altitude Area Defense missile defense system that Beijing has strongly objected to.

"We've also been very clear with Beijing that ... as long as North Korea continues to take these actions and to advance its nuclear and missile programs, and as long as that's not stopped and reversed, we will have to take steps to assure our own security and that of our partners and allies," he said. 

"None of these steps are directed against China, but it's also no secret that many of these steps are not ones that China is enthusiastic about. But we've been very, very clear that we will have to do it. The best example of that recently is the conversation that's begun with the South Koreans about the deployment of the THAAD missile system," he said.

Rose Gottemoeller, under secretary of state for arms control and international security, meanwhile, expressed satisfaction with the way China has been working with the U.S. to put together the U.N. Security Council sanctions and implement them.

"I have been quite heartened in my interactions with my Chinese counterparts about the degree in which China joins us in a very strong and intensive focus on ensuring good, solid implementation of the U.N. Security Council resolution," Gottemoeller said at a Foreign Press Center briefing.

"I always like to say the proof of the pudding is in the making. Now, we have to ensure strong implementation" of the resolution, she said. "And thus far, our cooperation with China on this has been very good," she added. (Yonhap)