YANGOON: Authorities in military-run Myanmar detained dozens of opposition party members on Sunday as they returned from ceremonies marking the death of the father of jailed pro-democracy leader Aung San Suu Kyi, witnesses said.

The arrests came after riot police set up barricades around the Martyr’s Mausoleum where the official ceremony took place to commemorate the death of Gen Aung San, the country’s independence hero.

At least 50 members of the opposition National League for Democracy party were walking in small groups when they were arrested, witnesses said.

It was not immediately clear why police detained them.

Some of the NLD members had been attending a ceremony at party headquarters to mark Gen Aung San’s death 62 years ago, while others had been at the official commemoration.

“Some members were roughly taken into trucks, and those who ran away were chased,” a witness said. Some who ran onto public buses were dragged out and taken away.

At least three journalists and cameramen who had been filming NLD members walking to the mausoleum were detained. They were released minutes later after police told them not to use video footage that showed heavy security.

Gen Aung San and other government leaders were assassinated by gunmen during a Cabinet meeting on July 19, 1947, shortly after Britain granted independence to the Southeast Asian colony.

Nobel Peace Prize laureate Aung San Suu Kyi marked the anniversary of her father’s death inside Yangon’s Insein prison. She is on trial on charges of violating the terms of her house arrest by giving shelter to an uninvited American man who swam to her lakeside home in May. If convicted, she faces up to five years in prison. Her trial is to resume Friday.

Earlier Sunday, hundreds of riot police erected barricades secured with barbed wire and blocked streets leading to the Martyr’s Mausoleum. More than two dozen trucks carrying riot police and four prison vans were parked near the monument, located near the famed Shwedagon pagoda.

Flags were flown at half-staff at the mausoleum as officials placed flowers at the tomb, and families of the slain leaders joined the tightly guarded wreath-laying ceremony.

Authorities allowed about 30 NLD members to pay tribute at the mausoleum but turned away others who wore T-shirts emblazoned with images of Aung San.