Tamil Tiger rebels acknowledged the death of their leader Sunday, nearly a week after the Sri Lankan government said it had recovered the body of Velupillai Prabhakaran and declared victory in the country’s 25-year civil war with the rebels. Prabhakaran “attained martyrdom fighting the military oppression of the Sri Lankan state” on May 17, according to Tamilnet.com, a rebel Web site, citing the group’s international affairs spokesman. On Tuesday, President Mahinda Rajapaksa declared victory against the Tamil Tigers.