Seoul, Mar 14 (IANS): The top nuclear envoys of South Korea, the US and Japan on Monday denounced North Korea's recent missile tests and called on Pyongyang to cease acts that could escalate tensions, Seoul's Foreign Ministry said.

Noh Kyu-duk, special representative for Korean Peninsula peace and security affairs, his US counterpart Sung Kim and Japan's Takehiro Funakoshi spoke on the phone amid rising tension on the Korean Peninsula over the possibility of Pyongyang's intercontinental ballistic missile (ICBM) system test, reports Yonhap News Agency.

The trio denounced the North's recent spate of ballistic missile launches as violations of UN Security Council resolutions and urged it to return to dialogue at an early date, the ministry said in a release.

They also agreed to closely monitor Pyongyang's moves and remain in close cooperation to respond to its acts, it added.

South Korea and the US accused Pyongyang on March 11 of having tested a new ICBM system on February 27 and March 5 ahead of a full-range missile test.

Seoul and Washington have detected signs that North Korea is preparing to conduct another ICBM firing as early as this week, according to informed sources.

Concerns have persisted that the North could engage in more provocative acts as it made a veiled threat in January to lift its years-long self-imposed moratorium on nuclear and ICBM tests.