Cambodia's veteran ruler Hun Sen in hospital in Singapore

PHNOM PENH (Reuters) - Cambodian Prime Minister Hun Sen, one of the world's longest serving rulers after more than three decades in power, is in hospital in Singapore, he said on his Facebook page on Thursday. Hun Sen, 64, said he had fallen ill because he was very tired and needed urgent medical treatment. He said he had been in hospital since Wednesday, but planned to return to Cambodia on Sunday to resume work as normal. Pictures showed him in bed with family members at his side. Hun Sen was briefly hospitalised in Singapore last year. The former Khmer Rouge guerrilla has ruled his southeast Asian country with an iron hand since 1985, a period in which Cambodia has emerged from the aftermath of genocide to become one of the region's fastest growing economies. Opponents accuse Hun Sen and his allies of promoting corruption and human rights abuses and of using unfair measures to undermine rivals in the run-up to local elections next month and a general election next year. The European Union called on the government on Thursday to respect the rights of five human rights workers detained for more than a year without trial in a political case. Last week, a court extended their detention for a further six months. (Reporting by Prak Chan Thul; Editing by Clarence Fernandez)