NEW DELHI, Jan. 14-- The Indian government has abruptly sacked the chief of the country's top defense research organization and architect of Agni series missile program, sources said Wednesday.

Avinash Chander, the chairman of Defense Research and Development Organization, who is famous for envisaging the long- range Agni series missile program, was removed from his post late on Tuesday evening, following a decision by the India Cabinet, the sources said.

He was on contract since his retirement in November last year, and was removed from his position with effect from the end of January, 15 months before his tenure was to end.

However, no reason has been given by the government for the removal of Chander, who is considered to be the man who helped India become a missile power against all odds.