By Ece Toksabay

ANKARA (Reuters) - More than a dozen suspected members of Islamic State appeared under police protection in an Ankara courtroom on Monday accused of involvement in Turkey's deadliest suicide bombing, which killed more than 100 people in the capital just over a year ago.

The defendants were brought into the courtroom under the protection of riot police in body armor and helmets, as families and lawyers of the victims chanted "murderers" and demanded the state also accept responsibility.

"If the security measures used to protect the killers today were taken during the rally, the Ankara train station massacre wouldn't have taken place," said Mahmut Tanal, a member of parliament for main opposition Republican People's Party (CHP).

The defendants were among 36 suspects, some still at large, on trial for plotting the double suicide bombing outside the main train station in Ankara on Oct. 10, 2015, which killed mainly young pro-Kurdish and left-wing activists at a rally.

The 35 Turks and one Kazakh face charges of murder, membership of a terrorist organization and seeking to change the constitutional order, according to the indictment. Some face multiple sentences of up to 11,750 years in prison.

The twin suicide bombing took place in NATO member Turkey 20 days before a fiercely contested general election, raising tensions between the authorities and opposition supporters among the Kurdish community, Turkey's largest minority.

"A comprehensive and effective investigation has not been carried out into the bombing. No state officials are accused of neglect in the indictment. How can we expect justice from such a trial?" lawyer Mehtap Sakinci Cosgun, whose husband was killed in the bombing, told Reuters outside the courtroom.

Turkish forces have been combating an armed campaign by Kurdish militants while Kurdish political organizations have also been the subject of arrests over the last week.

One of the suicide bombers was identified as Turkish citizen Yunus Emre Alagoz and the other as a Syrian citizen who has yet to be identified, according to the indictment seen by Reuters.

Three of the suspects on trial on Monday appeared by video link from the southern city of Gaziantep near the Syrian border, where the Islamic State cell responsible for the attack is thought to have been based.

Islamic State has grown increasingly active in Turkey. A gun-and-bomb attack blamed on the group at Istanbul's main airport in June killed 47 people, while the bombing of a Kurdish wedding in Gaziantep in August killed 57.

Turkey launched a military incursion into Syria shortly after the wedding attack in a bid to push the radical jihadist group away from its border and prevent Kurdish militia fighters from gaining ground in their wake.

(Reporting by Ece Toksabay; Editing by Nick Tattersall and Ralph Boulton)