AKIPRESS.COM - HBO's most-watched series, the medieval fantasy drama Game of Thrones, will likely continue for three more seasons, a network executive has said while defending the show's gritty violence, reports ABC News.

The sixth season is currently being filmed and executives, who had planned to run at least a seventh season, are discussing with the show's creators how much longer the show will extend beyond that, HBO programming president Michael Lombardo said.

"They are feeling two more years after six," Mr Lombardo said at a Television Critics Association meeting.

Mr Lombardo said he would like to have more beyond that and would also be open to a prequel to the story of the epic battle for the Iron Throne in the fictional kingdom of Westeros, based on George RR Martin's A Song of Ice and Fire books.

This year, Game of Thrones hit 20 million viewers on average for its fifth season, which received 24 Emmy nominations including a best drama nod.