Washington’s top envoy John Kerry warned North Korea on Tuesday that it faced "real consequences" over its ongoing nuclear and missile testing program.

Washington's top envoy John Kerry warned North Korea on Tuesday that it faced "real consequences" over its ongoing nuclear and missile testing program.

"Together we are determined... to make absolutely certain that DPRK understands that there are real consequences for these actions," he told reporters on the sidelines of a summit in Laos, using the official acronym for the authoritarian hermit state.

Tensions have soared since Pyongyang carried out its fourth nuclear test in January, followed by a series of missile launches that analysts say show the North is making progress toward being able to strike the US mainland.

UN sanctions against the communist state have been ratcheted up in response, but Pyongyang has continued to carry out missile launches, with the most recent one last week, trying to prove that sanctions are ineffective in curbing its weapons development.

Earlier this month, Washington and Seoul agree to deploy a sophisticated anti-missile system in South Korea, which can shoot down incoming enemy projectiles.