Turkish security forces have foiled 18 suicide attacks since the beginning of this year, three of them by intercepting vehicles planned for use as car bombs, Interior Minister Efkan Ala has said.
A car packed with explosives was detonated in Ankara this month next to military buses.
NATO member Turkey faces numerous security threats. It is part of a US-led coalition fighting ISIS in neighboring Syria and Iraq and is battling Kurdish militants in its southeastern region, where a two and a half year ceasefire collapsed last July triggering the worst violence since the 1990s.