Myanmar's Karen leader killed

BANGKOK, Thailand (CNN) -- The Karen National Union secretary-general Mahn Sha was shot and killed Thursday in what the ethnic rebel group is calling an assassination by the Myanmar junta, a KNU official told CNN.

Two gunmen attacked him at his home in Mae Sot, a town on the Myanmar-Thailand border, the official said.

The rebel group has received numerous warnings that Myanmar's military leaders were planning to target and kill KNU leaders, the official said.

Thai police Col. Pasawat Tangjui said the killing may have been the result of internal differences in the rebel group, The Associated Press reported.

No one has claimed responsibility for the murder, according to AP.

The killing comes less than a week after Myanmar's ruling junta announced a plan to hold a referendum on a new constitution in May and national elections in 2010 -- a plan denounced by pro-democracy opposition leaders.

KNU is a major rebel group that operates in the border area and is trying to establish autonomy for the Karen ethnic minority.

The government of Myanmar, also known as Burma, blames the KNU for waging attacks to destabilize the military junta that has run the country for two decades. E-mail to a friend

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