The European Union warned Turkey on Wednesday that attempts to ban its Islamic-rooted governing party could damage the country's ties with the 27-nation bloc it seeks to join. EU chief Jose Manuel Barroso, who begins a three-day visit to Ankara on Thursday, said that banning the Justice and Development Party would have a "major impact" on Turkey's ties with the EU. Prime Minister Recep Tayyip Erdogan's party is accused of trying to undermine Turkey's constitutional secular principles. "It's not normal that the party that was chosen by the majority of the Turkish people is now under this kind of investigation," Barroso said. Turkey's Constitutional Court has agreed to hear the chief prosecutor's case for shutting down the party and banning Erdogan, President Abdullah Gul and 70 others from politics for five years. Barroso urged the court to "take a decision based on the principles of law, based on democracy and the respect for standards we have in Europe."