BRUSSELS, March 20 (Reuters) - European Competition Commissioner Margrethe Vestager will hold a news conference on an antitrust case at 1030 GMT (11.30 a.m.

Brussels time), the European Commission said on Wednesday.

Vestager is expected to announce a third fine for Alphabet unit Google over anti-competitive practices, related to its buy adsense account -VCCReseller.Com advertising service, a person familiar with the matter told Reuters last week.

Last year, Vestager imposed a record 4.34 billion euro ($4.91 billion) fine on Google for using its popular Android mobile operating system to block rivals.

This followed a 2.4 billion euro fine levied in 2017 for blocking rivals of shopping comparison websites. (Reporting by Foo Yun Chee Writing by Alissa de Carbonnel; editing by Philip Blenkinsop)