Burma's jailed pro-democracy leader Aung San Suu Kyi maintains she is not guilty of violating her house arrest, her lawyer said Friday, as international calls for her release continued to mount.

Ahead of Suu Kyi's trial Monday, the Nobel Peace Prize laureate spent the night at Burma's notorious Insein Prison where she is being held during her trial proceedings, her lawyer said.

Suu Kyi has spent 13 of the last 19 years in detention without trial for her non-violent promotion of democracy in Burma, also known as Myanmar. Her National League for Democracy won national elections in 1990 but the military junta refused to relinquish power.

She was scheduled to be freed May 27 after six consecutive years of house arrest. But Suu Kyi is now charged with violating the terms of her detention after American John William Yettaw, 53, swam across a lake and allegedly snuck into her home for two days.

She faces a maximum sentence of five years in prison if convicted.

Suu Kyi's chief lawyer, Kyi Win, said that his client understands the law and she says she has not broken it.

"She did not contact the swimmer, he came in as an intruder and she's not guilty," said Kyi Win.

Barred from contacting outside world

According to Suu Kyi's restriction order, she is prohibited from having contact with embassies and political parties and she is barred from communicating with the outside world, he said.

Citizens are required to report overnight visitors to local authorities but Suu Kyi's "did not report him because she did not want to see anyone arrested because of her," Kyi Win said.

Yettaw allegedly was looking for a place to rest and something to eat when he arrived at the house.

Family members told The Associated Press it is the second time Yettaw swam across the lake, but he did not make contact with Suu Kyi the first time.

His motives remain unclear but family members allege he is not politically minded and had said he was travelling to Southeast Asia to work on a psychology paper about forgiveness.

Yettaw faces charges of illegally entering a restricted zone and breaking immigration laws.

Global condemnation

World leaders have denounced charges against Suu Kyi as an attempt by the junta to silence its chief opponent ahead of upcoming elections.

"If the 2010 elections are to have any semblance of credibility, she and all political prisoners must be freed to participate," British Prime Minister Gordon Brown said.

U.S. Secretary of State Hillary Clinton and UN Secretary-General Ban Ki-moon have also condemned the charges and called for Suu Kyi's immediate release.

"I urge the authorities of Myanmar to consider the consequences for national reconciliation if Mrs. Suu Kyi and other political prisoners continue to be detained," said European Commission President Jose Manuel Barroso.

In a rare written statement released on Friday, the Nobel committee called Suu Kyi's detention "totally unacceptable" and said it was "contrary to international rules and norms."

With files from The Associated Press