YANGON (AFP) - Myanmar democracy icon Aung San Suu Kyi was Tuesday convicted of breaching her house arrest and ordered to spend another 18 months in detention, sparking intense international anger at the ruling junta. The sentence provoked threats of fresh sanctions from the European Union because it means that the 64-year-old Nobel peace laureate will now remain locked up during elections promised by the ruling junta sometime next year. The court at Yangons notorious Insein Prison sentenced her to three years hard labour and imprisonment for breaching the terms of her house arrest following an incident in which a US man swam to her lakeside residence in May. But powerful junta chief Than Shwe signed an order commuting the sentence and allowing Suu Kyi to serve out a year-and-a-half under house arrest, Home Affairs Minister General Maung Oo said shortly after the verdict. Thank you for the verdict, a grim-faced Suu Kyi, wearing pink and light grey traditional Burmese dress, said after the courts announcement, according to an AFP reporter in the court. John Yettaw, 54, the American man who swam to her house, was sentenced to seven years of hard labour and imprisonment on three separate charges but it was not clear if the terms would run consecutively or concurrently. Two female aides who lived with Suu Kyi also had their sentences reduced to 18 months. The opposition leader and her assistants had both faced jail terms of up to five years. Suu Kyi was later driven back to the house under tight security and the road outside the crumbling villa was sealed off, Myanmar officials said. Minister Maung Oo had made a surprise entrance to the courtroom just minutes after the judgment was read out, saying that Suu Kyi would be kept under similar conditions to her previous time in detention. He said it could be shortened if she lives well in the suspended sentence. Aung San Suu Kyi is the daughter of General Aung San. This is also for the peaceful security of the country and also to move towards democratisation, said Maung Oo. Aung San, the countrys independence hero, was assassinated in 1947. Suu Kyi has already been in detention for 14 of the past 20 years since Myanmars ruling military junta refused to recognise her National League for Democracys landslide victory in elections in 1990. The case has drawn international outrage at Myanmars military regime amid claims that the junta was using the charges as an excuse to keep her locked up for the elections due in 2010. She was put on trial by the regime just days before the latest period of her house arrest was due to expire. The European Union vowed to take targeted measures by reinforcing sanctions against the regime. There was no immediate response from the United States, which also imposes sanctions on Myanmar. British Prime Minister Gordon Brown said he was saddened and angry at the verdict in the sham trial, and called for the United Nations Security Council to impose a worldwide embargo on the sale of arms to the Myanmar junta. French President Nicolas Sarkozy said new sanctions had to hit the junta where it hurt, especially in the wood and ruby sectors. Australia also called for tougher sanctions, expressing dismay at the conviction. Malaysian Foreign Minister Anifah Aman called for an urgent meeting of the Association of Southeast Asian Nations (ASEAN), of which Myanmar is a member, while Amnesty International called the verdict shameful.