Turkish NTV television news channel said the terrorist detained in Adana, a woman, was a member of the Kurdistan Workers' Party (PKK) banned in Turkey. She had five kilograms of A-4 plastic explosives on her, when she was detained.
Police sources said that a man detained in Mardin had an explosive belt with him consisting of A-4 explosives, which he planned to set off in a crowded place, and was also a PKK member.
The A-4 explosives seized from the terrorists are the same type used on Tuesday during an attack in the country's capital Ankara, when a 28-year-old suicide bomber detonated explosives near a shopping mall killing six and injuring 121 people.
Earlier in the day national newspaper Milliyet quoted a source in the Turkish security services as saying the Kurdistan Workers' Party, a militant group that aims to unite parts of Iraq, Syria and Turkey to create an independent Kurdish state, smuggled the A-4 plastic explosives to Turkey from their base in Iraq.
Security measures were tightened across the country with the start of the tourist season, particularly at coastal resorts popular with tourists from Russia, Germany, and other countries.
The attempted attacks Wednesday along with Tuesday's rush hour explosion threaten to destabilize the political situation in Turkey, which will hold general elections on July 22.