Russian President Vladimir Putin on Tuesday congratulated his Turkish counterpart Recep Tayyip Erdoğan on the results of the constitutional referendum, the Russian leader’s spokesman, Dmitry Peskov, told RIA Novosti.

According to preliminary results, the Turkish President Recep Tayyip Erdoğan-led “Yes” campaign has won Sunday’s referendum in Turkey by garnering 51.2 percent of the votes.

Eighteen constitutional amendments were put to the vote on Sunday, and according to which Turkey is to transition from a parliamentary to a presidential system of government.

Turkish opposition and international analysts stress, however, that with these amendments, Erdoğan is gaining the sole right to govern Turkey, and that this is perilous for democracy and freedoms in the country.

According to the OSCE observers, the referendum took place in a political environment in which fundamental freedoms essential to a genuinely democratic process were curtailed.