(CNN) -- The global drumbeat against what is widely considered the unlawful detention of Aung San Suu Kyi in Myanmar grew louder Wednesday with the launch of an online campaign to let supporters leave 64-word messages of support for her.
Aung San Suu Kyi was first detained in 1989 after mass protests against the military government.
The site, 64 for Aung San Suu Kyi (http://64forsuu.com), aims to collect as many messages as it can by June 19, when the pro-democracy advocate turns 64.
By early Thursday, nearly 3,000 messages had poured in -- from politicians, celebrities and other well-wishers.
"For too long the world has failed to act in the face of this intolerable injustice. That is now changing," British Prime Minister Gordon Brown said in his message. "We must do all we can to make this birthday the last you spend without your freedom."
Author Salman Rushdie, who shares a birthday with Suu Kyi, wrote that he "silently applauded" her endurance.
"This year, silence is impossible," he added. "It is not any action of yours, but your house arrest, which symbolizes the suppression of Burmese democracy, that is criminal. It is your trial, not your struggle, that is unjust. On this day, on every day, I am with you."
The call for Suu Kyi's release has intensified in recent days, as Myanmar tries the Nobel laureate on charges of subversion. The country's military junta, which has ruled since 1962, says she violated her house arrest when she offered temporary shelter to an American man who swam to her lakeside home.
Her supporters say the move is meant to keep her confined so she cannot participate in the general elections that the junta has scheduled for next year.
On Tuesday, U.S. President Barack Obama called for Suu Kyi's immediate and unconditional release from an "arbitrary" and "unjustified" detention.
"Aung San Suu Kyi's continued detention, isolation and show-trial based on spurious charges cast serious doubt on the Burmese regime's willingness to be a responsible member of the international community," Obama said.
Nine Nobel laureates, including Bishop Desmond Tutu of South Africa, also have called for her release, deeming her prosecution a "mockery" in a letter to U.N. Secretary-General Ban Ki-moon. Watch the U.N. secretary general explain what he is doing for Suu Kyi »
Suu Kyi, 63, has denied violating her house arrest.
Taking the stand for the first time Tuesday, Suu Kyi told a judge she did not learn immediately that the American, John William Yettaw, swam nearly two miles and snuck into her bungalow on May 3.
She was told about the visitor the next day by one of two housekeepers who are her sole companions in the heavily guarded residence.
Suu Kyi's two helpers are also on trial, as is Yettaw -- a 53-year-old former military serviceman from Falcon, Missouri.
He left the house late May 5.
Suu Kyi has said she did not report the intrusion because she didn't want Yettaw or anyone else to get in trouble.
But it is this silence that the Myanmar's military junta is trying her for.
The government said Yettaw's presence violated the conditions of Suu Kyi's house arrest. If convicted, she could be sentenced to three to five years in prison.
The country's regime rarely allows Suu Kyi any visitors, and foreigners are not allowed overnight stays in local households without government permission.
In his testimony, Yettaw frequently repeated that God sent him to Myanmar to protect Suu Kyi because he had a dream that a terrorist group would assassinate her.
Yettaw testified that four or five policemen saw him swimming across the lake to reach Suu Kyi's house. They didn't shoot at him, Yettaw said, but threw rocks.
He also testified that he had tried and failed to enter her house once before. Police found him, questioned him and then released him, he said.
That testimony fits with the defense's assertion that the government failed to protect Suu Kyi at the crumbling colonial-era house where she has been kept under house arrest for 13 of the past 19 years.
The military junta has regularly extended her confinement.
Her latest round of home detention -- after five years of confinement -- expired Wednesday, according to her supporters at home and abroad.
Though the government said it considered releasing her at the end of the term, it said it had no choice but to try her after she met with Yettaw.
She was put under house arrest in 1989. The following year, her National League for Democracy party won more than 80 percent of the legislative seats in the first free elections in the country in nearly 30 years.
But the military junta disqualified Suu Kyi from serving because of her house arrest, refused to step down and annulled the results.
Since then, the 1991 Nobel Peace Prize winner has been the face of Myanmar's pro-democracy movement.