Riot police behind barbed wire barricades ringed a notorious prison where pro-democracy leader Aung San Suu Kyi faced trial Monday for allegedly harboring an American man who swam to her lakeside home. The tight security came as activist groups, which spearheaded an uprising against Myanmar's military rulers in 2007, called for peaceful protest rallies in front of Yangon's Insein prison until Suu Kyi is freed. Nearly 100 Suu Kyi supporters were able to pass through one of the barricades. Defense lawyers said the trial had been scheduled for 10:30 a.m. (0300 GMT) but it was not immediately known whether it had begun. The ambassadors of Great Britain, France, Germany and Italy as well as an Australian diplomat were barred from entering the prison, but an American embassy official was allowed in since a US citizen is on trial. On the eve of Suu Kyi's trial, her defense lawyer said she was innocent of the charges, which could put her into prison for up to five years. "We call all political forces for Free Aung San Suu Kyi to mobilize all over Burma, by holding praying sessions in homes, places of worship ... and holding silent, peaceful rallies in front of Insein prison," said a statement from three activist groups. Burma is the old name for Myanmar and preferred by the military regime's opponents. The groups included an organization of Buddhist monks, who were at the forefront of the 2007 protests, which were brutally crushed by the regime. Security forces blocked all roads leading to the prison as several hundred riot police, many armed with guns, batons and shields, guarded the perimeter of Insein, where the regime has for years incarcarated political prisoners. Nearly 100 members of Suu Kyi's National League for Democracy were able to pass through the first ring of barricades around the prison but not the inner one. One young protester was seen being taken away by police. The group was led by Win Tin, a leading member of the league who was freed last September after 19 years of imprisonment for exposing human rights violations in Myanmar's prisons. "After listening to the sequence of events, it is very clear that there is no breach of conditions of her restrictions," lawyer Kyi Win said after visiting the Noble Peace Prize laureate in the prison over the weekend. Suu Kyi, 63, was charged Thursday with violating the terms of her detention by sheltering John William Yettaw, reportedly a Vietnam War veteran, who will also be tried along with two female assistants who have been with Suu Kyi since 2003. Suu Kyi had been scheduled to be freed May 27 after six consecutive years of house arrest, but the ruling junta was widely expected to once again extend her detention period. International lawyers say this would have been illegal under Myanmar's own laws. The latest charges are widely seen as a pretext for the government to keep Suu Kyi detained past elections it has scheduled for next year as the culmination of a "roadmap to democracy" which has been criticized as a fig leaf for continued military control. Myanmar has been ruled by its military since 1962. The regime lost democratic elections in 1990 but did not honor the landslide victory of Suu Kyi's party. In Monday's court session, Kyi Win said Suu Kyi's defense team will ask for an open trial and may also request bail. The prosecution is expected to call 22 witnesses during the trial. Kyi Win said Suu Kyi was ready to tell her side of the story. "She has always been ready to tell the truth," he said. On Sunday, a family member said Suu Kyi's personal physician, Tin Myo Win, was released by authorities a day earlier after being taken from his home on May 7, a day after Yettaw was arrested near Suu Kyi's lakeside residence, where she has been detained for more than 13 of the last 19 years. The family member spoke on condition of anonymity, citing possible reprisals by authorities. It is not known why Tin Myo Win was arrested. A spokesman for Suu Kyi's National League for Democracy earlier said the doctor's detention may have been related to the American swimmer, who has been labeled a "fool" by the pro-democracy movement. Her latest arrest has sparked a storm of international appeals to Myanmar's government to free her and to restore democracy in the country. In unusually sharp criticism from a Southeast Asian nation, Philippine Foreign Affairs Secretary Alberto Romulo said Sunday that his government was "deeply troubled and outraged" over the "trumped-up charges" against Suu Kyi. "We urge the government of Myanmar to resolve the matter speedily and to release Aung San Suu Kyi immediately and unconditionally," he said. Normally, members of the 10-country Association of Southeast Asian Nations, which includes Myanmar, refrain from criticizing one another. Exactly why Yettaw, of Falcon, Missouri, swam across the lake to see Suu Kyi remains unclear. After leaving, he was fished out of the lake by authorities about 1.2 miles (two kilometers) from her residence and taken into custody. "I cannot tell you what he was thinking when he made those swims or whether or not he considered the consequences for anyone but himself," said Yettaw's stepson Paul in an e-mail to The Associated Press Monday. "He knew he could be caught and arrested, though I am very sure it never occurred to him that Suu Kyi or her companions could also suffer from his choices," he said. His wife, Betty Yettaw, earlier described her husband as eccentric but peace-loving and "not political at all." According to his ex-wife Yvonne Yettaw, he said he went to Asia to work on a psychology paper about forgiveness. She said he suffered from post-traumatic stress disorder and a head wound during his military service. His former wife said Yettaw belongs to the Church of Jesus Christ of Latter-day Saints, commonly known as the Mormons, adding it was unlikely he was in Southeast Asia to proselytize for the church or convert the Nobel laureate. "As a family, we are very sorry for any additional problems that John's action may have caused Suu Kyi and her companions," his stepson said.