TOKYO - UN Secretary-General Ban Ki-moon called Tuesday on Myanmar's military-run government to free all of its political prisoners, including opposition leader Aung San Suu Kyi.

The UN chief, who arrived in Japan earlier in the day for a three-day visit, will travel to Burma on Friday in a diplomatic bid to win the release of the 64-year-old Nobel Peace Prize laureate, who has spent more than 13 of the past 19 years in detention without trial.

"First of all, they should release all political prisoners, including Daw Aung San Suu Kyi," Ban told reporters in Tokyo. Daw is a title of respect in Burma.

Suu Kyi is being held in Burma's notorious Insein prison and is being tried on charges of violating the terms of her house arrest after an uninvited American man swam to her closely guarded lakeside home last month and stayed two days.

Ban is set to arrive in Rangoon, Burma's commercial capital, on Friday -- the same day Suu Kyi's trial resumes -- and is hoping to meet with her, UN officials said.

In Tokyo, Ban met with Japanese Foreign Minister Hirofumi Nakasone to discuss Suu Kyi's trial and North Korea's nuclear and missile threats, according to the Foreign Ministry.

He is scheduled for talks with Prime Minister Taro Aso on Wednesday.

Ban's talks in Tokyo are also expected to centre on Iran, where incumbent Mahmoud Ahmadinejad was declared the winner of a June 12 election but opposition leader Mir Hossein Mousavi has claimed fraud, calling for a new vote.

Ban has urged Iran's leaders to heed "the genuine will of Iranian people," but he has not said what the UN might do.

On North Korea, the UN chief and the foreign minister are expected to urge the regime to give up its nuclear program and return to international disarmament talks.

Ban's three-day visit to Japan comes amid escalating tensions on the Korean peninsula following Pyongyang's second nuclear test on May 25 in defiance of a UN ban.

The United Nations punished the communist regime over the atomic test by expanding an arms embargo and authorizing ship searches on the high seas in a bid to derail its nuclear and missile programs.

North Korea lashed out at the UN sanctions, saying it would bolster its nuclear arsenal and threatening war. Pyongyang is also reportedly preparing for a third nuclear test and more long-range missile launches.

Ban, who served as South Korea's foreign minister from 2004-2006, is scheduled for talks with Aso on Wednesday after meeting Japanese business leaders. He leaves for Singapore on Thursday before heading to Burma on Friday.