SINGAPORE (AFP) - Opposition leader Aung San Suu Kyi "covered up" the truth by failing to report an American man in her home, a senior Myanmar official said, warning foreigners not to interfere in the case.

"It is no doubt that Daw Aung San Suu Kyi has committed a cover-up of the truth by her failure to report an illegal immigrant to the authorities concerned," Major General Aye Myint, Myanmar's deputy defence minister, told a security forum in Singapore.

"Thus there was no option but to open legal proceedings in accordance with the law," he said.

"She permitted him to stay.... She communicated, provided him food and shelter," Aye Myint said.

Aung San Suu Kyi, a Nobel peace laureate, is facing up to five years' detention on charges relating to the surprise visit of an eccentric American to her lakeside prison home in early May.

In his speech to regional security officials and experts, the general said the case against Aung San Suu Kyi was an internal matter for Myanmar to resolve without foreign intervention.

"Countries should refrain from interfering in the internal affairs of Myanmar that will affect peace and security of the region," sid Aye Myint.

"Solving one's internal affairs through its legal system with legal proceedings in accordance with law does not amount to the threat of peace or breach of security of the region," he said in an apparent reaction to criticism of the charges against Aung San Suu Kyi from other forum participants.

Ann Taylor, Britain's minister for international defence and security, said at the meeting earlier Sunday that Aung San Suu Kyi should be released.

"The continued imprisonment of Aung San Suu Kyi by the Burmese regime is a reminder that we cannot take for granted the institution of democracy," she said, referring to Myanmar by its former name.

"The people of Burma have suffered for nearly half a century of conflict and isolation, but Aung San Suu Kyi is not alone," Taylor said.

"People all around the world are standing with her and the Burmese people and we say to the generals: Now is the time for transition to democracy starting with the release of Aung San Suu Kyi."