RANGOON, Burma — Already under fire for its handling of cyclone victims, Burma’s military regime today renewed the detention of pro-democracy leader Aung San Suu Kyi and detained about 20 members of her opposition party.

The duration of the extension was not immediately known, the official said on condition of anonymity because he was not authorized to speak to the media. In the past, the junta has renewed Ms. Suu Kyi’s detention for six-month or 1-year periods.

Ms. Suu Kyi, a Nobel Peace Prize laureate, was personally informed of her continued imprisonment by officials from the Home Ministry who entered her villa prior to the announcement, the official said.

Under house arrest continuously since May 2003, Ms. Suu Kyi has long been the symbol of the regime’s brutality and the focus of a worldwide campaign that has lobbied for her release.

The extension was issued despite a Burmese law that stipulates no one can be held longer than five years without being released or put on trial.

The junta faced a deadline to extend Ms. Suu Kyi’s house arrest for another year or release her. Members of her National League for Democracy were marching from the party’s headquarters to her home when riot police shoved the group into a truck.

It was not immediately clear where the truck was headed or exactly how many people were detained.

Some of the detainees wore Suu Kyi T-shirts and others the party uniform, a peach colored jacket, sarong and cone-shaped hat. Thrown into the truck, two members seated by windows unfurled a 2-foot poster of Ms. Suu Kyi before being ordered to roll it back up.

As the detentions occurred, Ms. Suu Kyi’s party called for her immediate release and lashed out at the regime for having rammed through a new constitution via a “sham referendum.”

The decision by the junta to extend Ms. Suu Kyi’s latest period of house arrest will almost certainly ignite more criticism from the international community.

Ms. Suu Kyi has been confined for 12 of the past 18 years to her home in Burma’s largest city, Rangoon. She has long been the symbol of the regime’s brutality and the focus of a worldwide campaign that has lobbied for her release.

Ms. Suu Kyi received the Nobel Peace Prize in 1991 for her nonviolent efforts to overturn the regime led by Senior General Than Shwe.

The Indonesian Foreign Minister, Hassan Wirayuda, called today for her release, saying it would be a way of thanking the international community for its generosity after the cyclone.

“I hope for the best but to be frank I’m not optimistic,” he said.

Security was stepped up around Ms. Suu Kyi’s home, with about 20 plain clothes police officers standing guard while six truckloads of riot police were on guard near her National League for Democracy headquarters. These were reinforced by pro-junta thugs in civilian clothes.

About 200 NLD members attended a ceremony inside the headquarters to mark the 18th anniversary of the party’s landslide victory in 1990 elections, which the junta has never honored.

Burma has been ruled by the military since 1962. The current junta seized power in 1988 after brutally crushing a Suu Kyi-led uprising.

An extension of Ms. Suu Kyi’s arrest is almost certain to add to the international community’s outrage and frustration with the junta, which is accused of blocking international aid to some 2.4 million survivors of Cyclone Nargis. Official government estimates put the death toll from the May 2-3 storm at about 78,000, with an additional 56,000 people missing.

The junta has given some ground, promising to allow foreign aid workers into the most devastated areas. U.N. officials have expressed hope they will soon be able to help survivors — if the generals keep their word.

In its latest assessment report, the United Nations said the rate of 10-15 aid airlifts into Burma needed to be stepped up along with quick delivery to the hardest-hit areas.

“The critical danger remains of a potential second wave of deaths among those not so far reached or only reached with small amounts of assistance,” the report said.

The French aid agency Doctors Without Borders said its teams had entered remote villages around the Irrawaddy delta town of Bogalay where people had not eaten for three days.

The United Nations has estimated that less than half the 2.4 million people victimized by the storm have received emergency assistance.

Donor nations offered more than $100 million Sunday to help the country recover, but they warned they would not fully open their wallets until given access to the worst-damaged areas.

Burma’s leaders are leery of foreign aid workers and international agencies because they fear an influx of outsiders could undermine control.

The junta is also hesitant to have its people see aid coming directly from countries like America, which it has long treated as a hostile power seeking to invade or colonize the country.