SEOUL, June 29 (Reuters) - Samsung Electronics 005930.KS and SK Hynix 000660.KS plan to each build two new massive chip fabrication sites in South Korea's southwest region as part of a national project to build chip production "ecosystem" valued at 800 trillion won ($517.87 billion), the government said on Monday.

The plan was unveiled at the announcement of three new "mega-projects" by the country and the global chip giants to spur growth and dominate the AI sector.

($1 = 1,544.8000 won)