YANGON — A court in military-run Myanmar on Monday sentenced ousted leader Aung San Suu Kyi to six more years in prison after convicting her on four extra counts of corruption, according to a source familiar with the matter and local media reports.

The latest verdict in the series of secretive trials against the Nobel laureate takes her total jail term to 17 years and comes as the UN's Special Envoy on Myanmar traveled to the country on Monday to address the "deteriorating (rights) situation."

Suu Kyi, who turned 77 in June, has previously been found guilty of multiple offenses ranging from graft to election violations.

On Monday she was found guilty of misusing funds from a charity and leasing government-owned land at discounted prices, according to the CNN source.

Suu Kyi is being held in solitary confinement at a prison in the capital Naypyitaw and has denied all charges against her.

International rights groups and world leaders have expressed concern about the deteriorating state of human rights in Myanmar and dismissed ongoing trials against Suu Kyi, calling them "unfair and unjust."

"The Myanmar military junta's unjust conviction and sentencing of Aung San Suu Kyi is part of its methodical assault on human rights around the country," said Elaine Pearson, acting Asia director at Human Rights Watch (HRW), in a statement Monday.

"The military's willingness to forcibly disappear the country's high-profile civilian leader reveals the brutality that lesser-known political prisoners face," Pearson said.

Meanwhile, UN's Special Envoy on Myanmar, Noeleen Heyzer, traveled to Myanmar on Monday to address the "deteriorating situation and immediate concerns," the UN said in a statement.

"The Special Envoy's visit follows her extensive consultations with actors from across the political spectrum, civil society as well as communities affected by the ongoing conflict," the statement said. — CNN