State-owned New Light of Myanmar has reported that John William Yeattaw “secretly entered the house and stayed there” for at least two days. He was arrested late on Tuesday while swimming back across the lake, apparently using a five-litre water bottle as a buoyancy aid.
An American passport, a rucksack, a pair of pliers, a camera and US dollars were confiscated from him, the newspaper said.
Nobel Peace Prize Laureate Aung San Suu Kyi has spent 13 of the past 19 years under house arrest at her compound on University Road, in Yangon (pictured), which is on tightly-guarded Lake Inya where swimming is prohibited.
Such an incident would be the first time a foreigner made it inside Ms Suu Kyi's compound without a military permit.
Her latest period of detention is due to expire at the end of May and the authorities have not yet said if it will be extended.
A spokesman for the US embassy in Yangon said they had not been informed of the arrest and knew nothing about it.
A spokesman for the National League for Democracy said the incident showed the security weaknesses at the compound.
“We are worried for Daw Suu Kyi's security,” Nyan Win added.