BRUSSELS, June 29 (Reuters) - The extension of two Belgian nuclear power plants until 2036 is not enough to ensure energy supply security until then, Belgian grid operator Elia said on Thursday.

"We are safe for the coming winters, but there will be additional needs in the future," Elia CEO Kris Peeters told Belgian broadcaster VRT.

In a report, Elia said additional capacity in the future is needed to meet increased electricity demand, referring to the increase of electric cars on Belgian roads, among other factors, and called upon the Belgian government to invest in digitalisation, infrastructure as well as renewable energy. (Reporting by Charlotte Van Campenhout; Editing by Leslie Adler)