Twenty-nine Turkish police officers went on trial in Istanbul on Tuesday accused of involvement in the July 15 failed coup, the first trial of the alleged putschists to open in the city.

The suspects, 24 of whom are under arrest, went on trial at the gigantic courthouse by Silivri prison outside Istanbul, the state-run Anadolu news agency said.

The first hearings are expected to last four days and the session began with the reading out of the names of the accused as well as the indictment. This was expected to be followed by arguments for the defence.

The suspects are charged with refusing to obey orders to protect President Recep Tayyip Erdogan on the night of the coup.

If convicted, 21 suspects each face three life sentences and the other eight officers could be handed prison terms of between seven-and-a-half and 15 years.

Five months after the coup, small-scale trials of suspects have already began in the provinces but this is by far the most significant process to begin so far.