North Korea has successfully tested an upgraded long-range cruise missile and a warhead of a tactical guided missile this week, Reuters reported on Friday.

The country has tested six missiles in January, the highest in a month, according to The Associated Press. International law prohibits North Korea from testing nuclear weapons or ballistic missiles.

Two long-distance cruise missiles were fired on Tuesday, the Korean Central News Agency reported. They flew for more than 2 hours and 35 minutes along the East Sea of Korea and hit the target island 1,800 kilometres away.

“The launched two tactical guided missiles precisely hit the target island and it was confirmed that the explosive power of the conventional warhead meets the demand of its design,” the agency said.

On January 6, North Korea had successfully tested its second “hypersonic missile”, Al Jazeera had reported, citing Korean Central News Agency. Pyongyang had first tested a hypersonic missile in September.

The United States on Friday said that North Korea’s missile tests were “destabilising” and called on Pyongyang to “stop these provocations”, according to Reuters.

The European Union also said the tests posed a threat to international peace and security.