NEW YORK -(Dow Jones) - Burma's military rulers have tried to persuade Asian leaders that pro-democracy opposition leader Aung San Suu Kyi was detained May 30 because her National League of Democracy was plotting a violent uprising to overthrow the ruling junta, the Financial Times reported Thursday on its Web site.

The report said that in a personal letter to an unnamed Asian leader, a copy of which was obtained by the FT, Burma's senior general, Than Shwe, said his regime acted because NLD factions "were conspiring to create an anarchic situation... with a view to attaining power" by Suu Kyi's birthday on June 19.

The FT said letter said the NLD was trying to "arouse people to take to the streets... and create a mass movement that would result in public demonstrations and unrest," so it could seize government offices, factories and banks.

The letter also said Suu Kyi, a Nobel Peace Prize winner, was "attempting to lure armed groups... to join in the planned uprising," the FT reported.

Because of the "threat to national security by this militant group," the general said in his letter, he was "compelled to take firm measures to prevent the country from sliding down the road to anarchy and disintegration," the FT reported.

The report quoted a western diplomat who dismissed the letter as "fantasy."

"It reeks of weakness, not strength" the diplomat was quoted as saying.

Dissidents have said Suu Kyi was arrested after a pro-junta mob attacked her motorcade while she was on a political tour, killing up to 70 people. The government has said the motorcade tried to drive through a group of anti-Suu Kyi demonstrators, triggering a clash that left four people dead. The government has also said Suu Kyi is being detained to protect her from unidentified assassins.