South Korea's foreign ministry strongly denounced North Korea's defiant ballistic missile launches on Tuesday, vowing to take the necessary diplomatic actions to tighten the screws on the communist country.

Earlier in the day, North Korea test-fired three ballistic missiles into the East Sea from its central western county of Hwangju.

It was the communist country's first show of force after Seoul and Washington picked the southern county of Seongju, 296 kilometers southeast of Seoul, as the site to deploy the U.S.-built anti-ballistic missile interceptor system.

The decision to bring in the Terminal High Altitude Area Defense took place after months of careful deliberation.

Two of the missiles flew 500 to 600 km, apparently demonstrating the North's ability to target any place in South Korea.

"The (South Korean) government strongly condemns the latest launch, which is a blatant violation of relevant United Nations resolutions and a provocation threatening the safety and peace of the Korean Peninsula as well as the region," Cho June-hyuck, the Ministry of Foreign Affairs' spokesman, said during a press briefing. "We urge North Korea to stop this kind of provocation immediately."

Cho said South Korea will take the necessary diplomatic steps to stiffen international pressure on Pyongyang.

"Currently, there is an anti-North Korea frame set up around resolution 2270 in the international community," Cho said, referring to ongoing global efforts to enforce the toughest-ever U.N. resolution adopted against the reclusive country. The resolution passed in early March is in response to North Korea's earlier nuclear and long-range missile tests.

"The government is extending diplomatic efforts to further beef up this international collaboration framework and plans to take further measures locally if necessary," he said.

South Korea also expects China and Russia to remain engaged in the on-going U.N. efforts to censure North Korea for its latest launch of a submarine-launched ballistic missile (SLBM) despite their thorny diplomatic relations with Seoul over the deployment of the THAAD anti-ballistic missile defense system here.

On July 9, North Korea fired an SLBM off its east coast in a sign of anger over the THAAD deployment decision.

"Currently member countries of the U.N. Security Council are discussing measures to respond to North Korea's SLBM launch," Cho said.

The two countries have repeatedly voiced their intent to tighten their grip on North Korea's provocative actions, the spokesman said, indicating the THAAD row would not affect their stances on the matter.

North Korea stands prepared to conduct an additional nuclear test at any time, he also said. "If (the test) is conducted, the North would automatically face tougher sanctions and isolation." (Yonhap)