The South Korean navy held a rare live-fire drill near a set of disputed islands on Friday, brushing off angry protests from co-claimant Japan, which called the exercises "deplorable".

The defence ministry said the drill around the Seoul-controlled islets, called Dokdo by the South and Takeshima by Japan, were part of the military's "regular" national defence training.

A U.N. monitor Wednesday urged China to bring ally North Korea to heel over its record of systemic human rights abuse, likening Beijing's clout to that of Washington with Israel.

"How are we going to persuade China that they are in a position to do this? They don't accept that they have any kind of influence on the North Koreans," Marzuki Darusman told reporters.

Japan said Wednesday it would soon hold fresh official talks with North Korea after Pyongyang's surprise promise to investigate the Cold War kidnappings of Japanese nationals.

Chief Cabinet Secretary Yoshihide Suga, the top government spokesman, said the two governments had yet to decide when and where the talks would be held.

North Korea appears to have acquired a sea-based copy of a Russian cruise missile, the latest step in an effort to enhance its maritime strike capability, a U.S. think-tank said Tuesday.

A state propaganda film disseminated on social media sites, including YouTube, provides a very brief glimpse of the missile being launched from a naval vessel.

South Korea on Monday returned five North Korean fishermen rescued last week from their sinking boat off the east coast, officials said.

The repatriation took place just after 4:00 pm (07:00 GMT) at the border truce village of Panmunjom, the South's unification ministry said.

Japan and North Korea are preparing to hold fresh talks after Pyongyang's surprise pledge to probe the Cold War kidnappings of Japanese nationals, a report said Sunday.

Japan's Kyodo news agency said the two sides may meet again late this month, after Japan said on May 29 that it would ease sanctions against North Korea if the secretive state delivers on a pledge to reinvestigate the cases of Japanese citizens snatched in the 1970s and 1980s to train spies.

North Korea on Thursday rejected Seoul's call for talks on the fate of a South Korean missionary sentenced to hard labour for life for allegedly spying and operating an underground church.

South Korea proposed Tuesday that the two sides should meet at the border truce village of Panmunjom for discussion on Kim Jeong-Wook, who was captured in the North last October.

Singapore said Tuesday it has filed criminal charges against a shipping firm based in the city-state accused of helping smuggle missiles and other military hardware from Cuba to North Korea.

The foreign affairs and home affairs ministries said in a joint statement that the charges were filed against Chinpo Shipping Company Pte Ltd and a Singapore citizen identified as Tan Hui Tin.

The U.S. tourist being held in North Korea loves adventure and "new cultures," his family's attorney said in a statement Monday.

North Korea said Friday that the U.S. citizen was detained for "hostile activities" after he reportedly left a bible at a hotel, bringing to three the number of Americans held by the reclusive regime including missionary Kenneth Bae.

North Korea on Monday warned of "strong" action against a U.N. office which will be set up in South Korea to monitor human rights violations in the communist country.

The North's Committee for the Peaceful Reunification of Korea slammed South Korea for accepting a request from the Geneva-based Office of the High Commissioner for Human Rights to open a field office in Seoul.