Turkish President Tayyip Erdogan addresses his supporters during an opening ceremony in Mersin, Turkey, February 3, 2017. Kayhan Ozer/Presidential Palace/Handout via REUTERS

ANKARA (Reuters) - Turkish President Tayyip Erdogan urged Turks on Tuesday to vote in favor of strengthening the presidency in a referendum, saying failure to do so would encourage militant groups trying to divide the nation.

Erdogan said he was still evaluating a parliamentary bill on constitutional changes to create an executive presidential system in Turkey and would give a response this week.

Once Erdogan approves the bill, a referendum will be held most likely in April, which, if passed, could lead to him holding office until 2029.

“I believe my people will never give a positive sign to Qandil, Imarali, and those terrorizing out country,” he told a news conference.

He was referring to the Qandil mountains of northern Iraq, where the Kurdistan Workers Party (PKK) militant group has bases, and to the island prison of Imrali, where its leader has been jailed since 1999.

Erdogan accuses members of the pro-Kurdish Peoples’ Democratic Party (HDP), which opposes the executive presidency, of links to the PKK, deemed a terrorist organization by the European Union and United States.

Erdogan has cast the stronger presidency as needed by Turkey at a time when it is fighting Islamic State, the PKK, and after a failed coup.

Turkey blames the network of U.S.-based cleric Fethullah Gulen, which it calls the Gulenist Terrorist Organization (FETO), for the coup attempt and has sought to shut it down at home and abroad.

Visiting Ethiopian President Mulatu Teshome Wirtu said he would shut down Gulen’s schools and hand them over to Turkey’s Maarif (Education) Foundation.