A dozen Iranian nuclear experts visited North Korea last week to observe its failed rocket launch on Friday, South Korean state news agency Yonhap's Washington correspondent reported on Sunday.

"On March 31, 12 Iranians of the Shahid Hemmat Industrial Group (SHIG) arrived in North Korea. "The Iranians undoubtedly were there to observe the missile launch and receive test data from North Korea," the correspondent quoted a diplomatic source, who wished to remain anonymous, as saying.

Defying international pressure, Pyongyang launched a long range missile, but U.S. and South Korean officials said it crashed into the sea a few minutes after launch, dealing a blow to the reclusive state

The launch of the three-stage Unha-3 rocket took place at 7:39 A.M. local time on Friday, according to South Korean officials. Pyongyang has claimed that the launch was meant to place a communications satellite in space, but the U.S., Japan, South Korea and other nations view it as part of North Korea's attempt to advance its military ballistic missile capacity.

The launch was timed to celebrate the 100th birthday of Kim Il-sung, the deceased founder of the state, and to coincide with the ascent to power of his grandson Kim Jong-un.

North Korea admitted its long-range rocket failed to deliver a satellite into orbit on Friday, and the U.S. condemned the provocative action as a threat to regional security.

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