YANGON - POLICE in Myanmar arrested a prominent human rights activist on the 20th anniversary of massive pro-democracy protests, a colleague of the detained man said on Saturday.

Myint Aye, 57, was arrested on Friday evening after police searched his home in Kyimyindine township, a suburb of Yangon, said Mr Maung Maung Lay.

The reason for the arrest was not immediately known. Police released no information.

Myint Aye and Mr Maung Maung Lay are both members of the group Human Rights Defenders and Promoters, which Myint Aye founded in 2002.

Myint Aye has been arrested and imprisoned at least five previous times since 1988, most recently in August 2007, Mr Maung Maung Lay said. He also has served as an official in the opposition National League for Democracy party.

In March, he was attacked on the street by two unidentified men, requiring hospitalisation and four stitches on his head. The assault was one of several staged at the time against opponents of the new constitution backed by the military government.

Myint Aye's arrest came on the anniversary of nationwide pro-democracy protests in 1988 that were violently suppressed by the military.

Only one serious public demonstration is known to have taken place on Friday, in the western Rakhine State.

Asked if Myint Aye's arrest was connected to any anniversary protest, Maung Maung Lay said his colleague was more concerned with promoting human rights than engaging in political activities. He said Myint Aye was able to prepare for jail, bringing along clothes and medicine for his diabetes when he was taken away by police.

Earlier, Myanmar authorities released 43 demonstrators who held one of the country's few protests marking the anniversary of the 1988 pro-democracy uprising, an opposition party official said on Saturday.

No significant protests were reported in Yangon, the country's biggest city, where security personnel were brought out in large numbers to stave off any trouble.

Activists there performed small gestures, such as laying flower baskets with slogans by a roadside.

A group of 48 young protesters marched peacefully on Friday in Rakhine State, a western province, which is one of the military-ruled country's more active areas for anti-government protests.

The marchers, some wearing white T-shirts with the number 8-8-88 to mark the occasion, complied with a police request to surrender, said Mr Thein Naing, joint secretary of the Rakhine State organizing committee of the National League for Democracy party.

He said 43 of the marchers were released on Friday night.

'I hope those remaining five will also be released as they had not done anything to harm the peace,' said Mr Thein Naing. 'They did it in memory of those who were killed in 1988 and I hope the authorities who have declared plans to establish democracy in the country will treat those youths leniently and release them quickly.'

Taunggok and other parts of Rakhine saw militant protests during large pro-democracy demonstrations in September, which were violently suppressed by the military.

Some of the bigger pro-democracy protests held since that time have also been in the area, while most of Myanmar remains subdued. -- AP, AFP