Burmese authorities have been arresting activists and opposition party members in the commercial capital Rangoon, as they staged vigils for the release of opposition leader Aung San Suu Kyi. As Ron Corben reports from Bangkok, about 50 people have been detained in recent days.

The authorities moved quickly to detain activists Wednesday as they prayed for the release from house arrest of Burma's Nobel laureate and opposition leader, Aung San Suu Kyi.

Witnesses say police moved in as the group prayed at a Buddhist pagoda on the outskirts of Rangoon. Other activists had been detained on Tuesday as they tried to hold similar vigils.

Among those detained was labor activist Su Su Nway.

The latest protests came after the opposition National League for Democracy forwarded a letter to the military government's leader, General Than Shwe, asking that Aung San Suu Kyi be released.

Debbie Stothardt from the human rights group, Alternative ASEAN Network, says the arrests highlight the military's fears of any opposition.

"They are extremely afraid of any sort of organized action, so that just the mere act of praying for Aung San Suu Kyi's release becomes a very big threat," said Stothardt. "The regime is very, very fragile. They are on the defensive because they have been targeted for criticism by their own people on economic grounds and on political grounds."

Burma's economy is one of the poorest in Southeast Asia, and it has been hurt by rising costs linked to higher global fuel prices. In February a brief protest was held in central Rangoon over high prices and to call for improved health care, education and pension benefits.

This week's arrests came as almost 60 former world leaders called for Aung San Suu Kyi's immediate and unconditional release from house arrest. The former leaders include Jimmy Carter, George H.W. Bush and Bill Clinton from the United States, former Thai Prime Minister Chuan Leekpai, and Kim Dae-jung of South Korea.

The current detention order for Aung San Suu Kyi is to expire on May 27, but it may be extended by the military as it was last year.

May 27 is also the anniversary of Burma's last general elections in 1990, when the National League for Democracy won a landslide victory, but the military refused to allow the party to take power.

Aung San Suu Kyi has spent 11 of the past 17 years in detention, despite regular calls for her freedom and her party's requests for a dialogue with the military on political reform.