Worldwide condemnation followed Myanmar's six-month extension of the house arrest of opposition leader Aung San Suu Kyi, with officials from the UN, EU and US expressing frustration and regret.

Suu Kyi has been under continual house arrest for the past five years. Since returning to the country in 1988, she has spent 12 years under house arrest.

Early Tuesday, police arrested 18 supporters of the Nobel peace laureate who were protesting her detention, opposition sources said.

The latest extension of her open-ended detention came on the 18th anniversary of the landslide election of Suu Kyi's National League for Democracy (NLD) in Myanmar's last general election. The junta refused to recognize those election results.

In New York, UN Secretary General Ban Ki-moon called the extension "regretful."

"The sooner restriction on Daw Aung San Suu Kyi and other political figures are lifted, the sooner Myanmar will be able to move towards inclusive national reconciliation, the restoration of democracy and full respect of human rights," Ban said.

The UN has been demanding the junta open up the country to international relief aid to victims of the cyclone Nargis, which has killed more than 70,000 and left another
50,000 still missing.

European Union foreign policy chief Javier Solana called the arrest extension "very sad and frustrating," coming at a time when so many countries and organizations were focusing on providing assistance to the people affected by the cyclone.

"The EU is doing its best to this effect. However, it continues to be deeply concerned by the political situation. Transition to democracy remains important for the future of Burma/Myanmar," Solana said.

Benita Ferrero-Waldner, the EU's external relations commissioner, said she was "personally disappointed that a historic opportunity was missed to give a sign of reconciling political life in Myanmar at a time where national and social cohesion, and solidarity and dialogue, are more needed than ever."

US President George W Bush said he was "deeply troubled" by the decision of Myanmar's ruling junta to extend the detention.

The EU and US called upon the regime to release Suu Kyi and all political prisoners. Bush repeated past calls for the government to "begin a genuine dialogue with Aung San Suu Kyi."

The 18 NLD members were arrested by plainclothes' policemen as they marched from their headquarters to Suu Kyi's Yangon home. They were taken in two vehicles to an unknown destination.

Suu Kyi and Tin O, party vice-chariman, have been under house arrest since May 30, 2003, when authorities charged her with threatening national security after pro-government thugs attacked her and her followers in Depayin, northern Myanmar, killing 70 NLD supporters.

According to Myanmar law, the government cannot keep prisoners charged with undermining national security under detention for more than five years. (dpa)