A lawmaker from Turkey's main opposition CHP said on Friday he had submitted an appeal to the European Court of Human Rights demanding the annulment of a referendum that granted President Tayyip Erdogan sweeping executive powers.

Musa Cam, a lawmaker for the Republican People's Party (CHP) from the coastal city of Izmir, told Reuters he submitted an individual appeal independently from the one the party is expected to make to the European Court.

In his application, Mr. Cam said the decision by Turkey's High Electoral Board (YSK) to allow unstamped ballots in the referendum had caused the outcome to be "illegitimate and not representative of the people's will".

Final results released by the YSK on Thursday showed 51.4 percent support for the “Yes” vote to approve the biggest changes to Turkey's political system in its modern history.

The results, which matched the preliminary figures released in the hours after polling closed on April 16, were released despite calls by the CHP to delay a final announcement while they appealed the vote. The YSK and a Turkish court, the council of state, have rejected or declined to hear the CHP appeals.

President Erdogan and the “Yes” camp have said appeals were an attempt to undermine the results of the vote, adding only the YSK had jurisdiction on the matter.

The package of 18 amendments passed in the referendum gives the president the authority to draft the budget, declare a state of emergency and issue decrees overseeing ministries without parliamentary approval.

With the changes, Mr. Erdogan will also immediately be eligible to resume membership of a political party. He told reporters on Tuesday that he would rejoin Turkey's ruling AK Party once the full results came out, and a senior official said he would be named as a candidate to lead it at an extraordinary congress on May 21.