Turkey's main opposition Republican People's Party (CHP) appealed to the country's top court on Friday against a government-backed constitutional amendment bill, launching a legal battle with the ruling party over the controversial reform, Xinhua reported.
The CHP filed the petition at the Constitutional Court on Friday morning to annul the bill, which was approved by Turkish President Abdullah Gul on Wednesday and was expected to be put to a referendum later this year.
Turkey's Higher Electoral Board (YSK) said Thursday the country plans to hold a referendum on the bill on Sept. 12.
The YSK decision will be valid if the top court does not annul the reform bill, according to the Turkish newspaper Hurriyet Daily News.
Proposed by the ruling Justice and Development Party (AKP), the bill has been strongly criticized by opposition parties and the judiciary as an AKP attempt to seize more control over the judiciary and other state institutions.
The AKP says Turkey needs to change its current constitution, adopted after a 1980 military coup and criticized by the European Union (EU), to improve democracy and human rights to EU standards, which Ankara seeks to join.
With Turkey's general elections to come next summer, the row over the reform bill has aroused concerns for tensions. However, Turkish Prime Minister Recep Tayyip Erdogan has repeatedly ruled out the possibility of an early election.
Among the most heavily-debated amendment proposals are those to require the permission of a parliamentary commission for closure of political parties, allow civilian court trial of military personnel in certain crimes and overhaul the judiciary.
The article that would make it harder to close political parties was rejected during parliament voting.
Nearly 20 political parties have been shut down since the current constitution came into effect in 1982. The AKP itself was the target of a closure case in 2008 on charges of undermining the secular system but was not banned.