South Korea and the United States warned Friday that North Korea will face a "stronger and graver" response if it makes yet additional provocations in defiance of the international community.

Seoul's new nuclear envoy, Kim Hong-kyun, issued the warning after holding talks with his U.S. counterpart, Amb. Sung Kim, amid growing nuclear and missile threats from the communist nation.

"We agreed to focus on putting strong pressure on North Korea so as to create an environment where the North cannot help but change its behavior," Kim told reporters at the State Department.

"We also agreed to explicitly warn the North that it will face a stronger and more grave response if it makes another provocation."

The talks came as Pyongyang has sharply been ramping up nuclear and missile threats as South Korea and the U.S. have been conducting joint annual military exercises that the North has denounced as a rehearsal for invasion.

The North has threatened preemptive strikes, conducted banned short-range missile launches, and unveiled photos of what it claimed was a miniaturized nuclear warhead. On Friday, leader Kim Jong-un also called for bolstering nuclear capabilities with more tests.

White House press secretary Josh Earnest said the North has "a long history of provocative acts and destabilizing actions," especially at times of Korea-U.S. military exercises.

"But we obviously take the threat from North Korea quite seriously. After all, that's why we conduct these international military exercises, to ensure that our forces are ready to protect our allies in South Korea and our other allies like Japan, who could also be at risk," Earnest said.

The South Korean envoy said that the two sides share the view that now is the time to concentrate on full implementation of the new U.N. Security Council sanctions resolution, and it is premature to talk about dialogue with Pyongyang.

"In addition, we reaffirmed our consistent principle that denuclearization should be the top priority in any talks with North Korea," he said.

China has proposed to pursue peace treaty talks with the North in tandem with denuclearization negotiations as a way to defuse heightened tensions on the Korean peninsula in the wake of Pyongyang's nuclear and missile tests.

Signing a peace treaty, which would replace the armistice that halted the 1950-53 Korean War, has been one of Pyongyang's long-running goals, but the U.S. and South Korea have demanded the North abandon its nuclear program first.

Kim said that the two sides appreciated China's role in adopting the new sanctions resolution and agreed to further strengthen cooperation with Beijing in carrying out the resolution and seeking the North's denuclearization.

It was the first time that Kim Hong-kyun, Seoul's new special representative for Korean Peninsula peace and security affairs, has met with U.S. Amb. Kim, special representative for North Korea policy, since he took office last week.

Kim also held meetings with officials of the White House and the Treasury Department. (Yonhap)