* North Korean man arrested, three suspects at large
* Malaysian police say autopsy not completed
* North Korea will reject autopsy report, demands body (Adds China coal import ban)
By Emily Chow and Liz Lee
KUALA LUMPUR, Feb 18 (Reuters) - Malaysian police said on Saturday they had arrested a North Korean man in connection with the murder of the estranged half-brother of North Korean leader Kim Jong Un, as a diplomatic spat over his body escalated.
Kim Jong Nam died this week after being assaulted at Kuala Lumpur International Airport with what was thought to be a fast-acting poison. South Korean and U.S. officials have said he was assassinated by North Korean agents.
Malaysian police said the latest arrest connected with the murder was made on Friday night, and the suspect was identified as Ri Jong Chol, born on May 6, 1970. He was in possession of a Malaysian i-Kad, which is an identification card given to foreign workers, they added.
"He is suspected to be involved in the death of a North Korean male," read a statement.
The police chief for Selangor state, Abdul Samah Mat, said the suspect had been remanded in police custody.
Two female suspects, one an Indonesian and the other carrying Vietnamese travel documents, have already been arrested, while a Malaysian man has been detained. At least three more suspects are at large, government sources have said.
Kim Jong Nam, the eldest son of the late North Korean leader Kim Jong Il, had spoken out publicly against his family's dynastic control of isolated, nuclear-armed North Korea.
South Korea's intelligence agency told lawmakers in Seoul that Kim had been living with his second wife in the Chinese territory of Macau, under China's protection.
He had been at the Kuala Lumpur airport to catch a flight to Macau when he was killed. An autopsy is being performed at a hospital in the capital city.
Selangor state police chief Abdul Samah told Reuters that the autopsy report was not complete yet. He dismissed media reports that a second autopsy would have to be conducted.
North Korea said in the early hours of Saturday that it would categorically reject Malaysia's autopsy report on the death of Kim Jong Nam, and accused Malaysia of "colluding with outside forces", in a veiled reference to rival nation South Korea.
Malaysia hit back by saying the country's rules must be followed. The foreign ministry has yet to make any comment.
Health minister Dr S.Subramaniam told state news agency Bernama that Malaysia was waiting for the toxicology report to complete the autopsy.
He said the autopsy report would hopefully be released "within this week".
The case threatens to weaken North Korea's ties with Malaysia, one of the few countries that has maintained good diplomatic relations with Pyongyang.
North Korea's nuclear arms and weapons programmes have alarmed the West, most recently its test of a ballistic missile earlier this month in its first direct challenge to the international community since Donald Trump became U.S. president.
Pyongyang's main ally and trading partner is China, which is irritated by its repeated aggressive actions but rejects suggestions from the United States and others that it could be doing more to rein in its neighbour.
On Saturday, China said it had further tightened trade restrictions with North Korea by suspending all imports of coal starting Feb. 19, although it did not say why. Coal exports to China are a vital source of revenues for Pyongyang.
ROW OVER AUTOPSY
Kim Jong Nam was assaulted at the low cost terminal of Kuala Lumpur International Airport on Monday with what is believed to be fast acting poison before he could board a flight to Macau. He sought help but died on the way to the hospital.
North Korea demanded on Friday night that Kim Jong Nam's body be released immediately. It had earlier tried to persuade Malaysian authorities not to carry out an autopsy.
"The Malaysian side forced the post-mortem without our permission and witnessing," the North Korean ambassador Kang Chol told reporters outside the hospital where the body of Kim Jong Nam is being kept.
"We will categorically reject the result of the post mortem ... "
He said Kim Jong Nam had a diplomatic passport and was under the consular protection of North Korea. (Additional reporting by Meng Meng and David Stanway in Beijing; Writing by Praveen Menon and A. Ananthalakshmi; Editing by Michael Perry and Mike Collett-White)
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