Among those found guilty by the court were Arisman Pongruangrong, Nisit Sinthuprai, Surachai Danwattananusorn, Singthong Buachum, Worachai Hema, and Payap Panket.
Singthong, a Pheu Thai Party politician, said yesterday that the convicted red-shirt leaders would appeal the verdict.
During that year, leaders from Asean and its dialogue partners had gathered for the summit in the resort city of Pattaya.