South Korea to halt North Korea rocket debris search

South Korea is to end its search for debris from North Korea's failed rocket launch without finding any fragments, its defence ministry said.

Muddy waters in the Yellow Sea, over which the rocket disintegrated on Friday, hampered the search of naval ships and helicopters, officials said.

The North said the rocket would launch a satellite, but critics saw it as a banned test of missile technology.

The UN on Monday strongly condemned the launch and ordered tighter sanctions.

At least 10 South Korean warships have been combing the waters where the Unha-3 rocket fell after exploding, 165km (105 miles) west of the South Korean capital, Seoul.

"No debris has been found and the operation will end officially at 17:00 (08:00 GMT)," a defence ministry spokesman was quoted by AFP news agency as saying.

Vessels from China, Russia and the US have also been searching for rocket debris, South Korean officials have said. Experts say the debris could offer an insight into the technology used by the North.

The North had warned before the launch that any attempts by other nations to retrieve any debris would result in "ruthless" retaliation.

On Monday, the 15-member UN Security Council, which includes North Korean ally China, said in a statement that the launch highlighted "grave security concerns" in Asia.

It ordered new items to be placed on North Korea's sanctions list, and a revision of the list of people and businesses subject to asset freezes.

The Security Council has already imposed tough sanctions on North Korea after rocket launches in 2006 and 2009.

Pyongyang agreed in February to a partial freeze on nuclear activities and a missile test moratorium in return for US food aid. But that deal was put on hold last month after the North announced its rocket launch plans.

Under the deal, UN nuclear inspectors would have been allowed into the country. But reports from Japan, citing unnamed senior US diplomats, said Pyongyang had now put talks on this aspect of the deal on hold.