VIENNA/BERLIN Up to 2.5 million votes could have been manipulated in Sunday's Turkish referendum that ended in a close "yes" vote for greater presidential powers, an Austrian member of the Council of Europe observer mission said on Tuesday.
Turkish President Tayyip Erdogan has dismissed criticisms of the vote, saying foreign observers should "know their place".
The mission of observers from the 47-member Council of Europe, the continent's leading human rights body, had already pronounced the referendum to be an uneven contest.
Support for "Yes" dominated campaign coverage, and the arrests of journalists and closure of media outlets silenced other views, according to Council of Europe and OSCE monitors.
Alev Korun, an Austrian member of the Council's observer team, said there were questions about the actual voting as well.
"There is a suspicion that up to 2.5 million votes could have been manipulated," added Korun, a Greens member of the Austrian parliament.
The pro-Kurdish opposition Peoples' Democratic Party said it presented complaints about unstamped ballots affecting 3 million voters, more than twice the margin of Erdogan's victory. »