An international human rights group says it has evidence that Burma's army used chemical weapons against rebels from the Karenni ethnic minority.
The Christian Solidarity Worldwide group alleges the incident took place in February during a shelling of the Karenni camp near Burma's northwestern border with Thailand.
Karenni fighters say the shells fired at them emitted a yellow vapor that left many of them sick, vomiting blood, and unable to walk.
The president of the group Dr. Martin Panter says he interviewed five soldiers and concluded they had symptoms consistent with a chemical attack.
Karenni rebels have been engaged in a long-running war with Burma's military to fight for greater autonomy from the central government.