Diplomats were allowed to meet Aung San Suu Kyi on Wednesday
Burma's military regime has blamed the incident which led to the arrest of opposition leader Aung San Suu Kyi on "anti-government elements".
State media quoted the foreign minister as saying that a visit to the home of Ms Suu Kyi by a US national was a stunt designed to embarrass the government.
Ms Suu Kyi is accused of breaking the terms of her house arrest and faces up to five years in jail if convicted.
Witnesses are continuing to testify at her trial, which began on Monday.
The trial of Aung San Suu Kyi has been widely condemned - not just by Burma's Western critics, but by its Asian neighbours too, as a ruse to keep her locked up until after the elections scheduled for next year.
In an apparent response to the criticism, the Burmese authorities made a rare concession earlier this week, allowing some journalists and foreign diplomats to observe the trial at Rangoon's Insein jail for a day.
Burma's Foreign Minister U Nyan Win defended the government's actions by saying the incident - when the American man swam to her heavily guarded lakeside house - had been fabricated by "internal and external anti-government elements".
He was quoted in the New Light of Myanmar as saying the stunt had been "trumped up to intensify international pressure" on Burma.
Conviction 'almost certain'
Government witnesses have continued to give evidence, producing numerous photographs taken by US national John Yettaw while he was at the house, and two Arabian-style women's gowns, which he allegedly used to disguise himself.
He is reported to have testified that he made the risky visit because he had a dream that she would be assassinated.
Ms Suu Kyi's lawyers say she tried to send the man away, but he refused to go, and that she only allowed him to stay because he said he was exhausted.
Diplomats expect the trial to finish next week, and believe she will almost certainly be convicted.
Ms Suu Kyi has been in detention for more than 13 of the past 19 years.
Her latest period of house arrest was scheduled to expire on 27 May, and many observers see this case against her as a pretext to ensure she is still in detention in 2010, when Burma's ruling generals say they will hold multi-party elections.
Aung San Suu Kyi's National League for Democracy party won the last elections, in 1990, but was never allowed to take power.