Council of State - the highest administrative court - in capital Ankara rejected People's Party's (CHP) appeal that challenged the results of the April 16 referendum allowing transition from current parliamentarian system to a presidential one.
A top Turkish court on Tuesday rejected an opposition appeal against the highest electoral authority's decision on the country's recent referendum results.
The Council of State - the highest administrative court - in Ankara rejected People's Party's (CHP) appeal that challenged the results of the April 16 referendum, in particular the Supreme Election Board's (or YSK) decision to count unstamped ballot papers.
Missing stamps are at the heart of the controversy surrounding the result of Turkey's referendum on 18 constitutional amendments.
CHP had first submitted a petition to cancel the referendum result which the board rejected. The party then approached the top court urging the official referendum results be suspended until the legal process ends.
However, the court also rejected the appeal and backed the law that no appeals could be made against YSK decisions at any court.
CHP's options remain limited now.
The CHP had said it would employ all legal channels to challenge the result, including at Turkey's Constitutional Court and the European Court of Human Rights.
Voters went to the polls last week to decide whether to approve changes to the country's constitution, which would bring shift from current parliamentarian system to a presidential one.
Unofficial results show the 'yes' campaign won with 51.41 percent, while the 'no' vote stood at 48.59 percent. Voter turnout was 85.46 percent.
The official results are due to be released by the election board in May. Turkey will shift to a presidential system in November 2019.