Turkish authorities have arrested 22 suspected radical leftists in the southern city of Antalya, a day after a hostage siege in an Istanbul courthouse in which a senior prosecutor and his leftist captors were killed.

Acting on a tip-off, police on Wednesday 1 April detained 22 students, all of them linked to the outlawed Marxist Revolutionary People's Liberation Party-Front (DHKP-C), the group behind Tuesday's drama, the AFP reported.

During the siege, gunmen from the banned Marxist revolutionary group had released images of a gun being held to the head of Mehmet Selim Kiraz, as the hostage crisis unfolded.

A statement posted online said the prosecutor would be killed if the group's demands were not met. The prosecutor was shot in the head and several other parts of his body and underwent surgery, Turkish President Recep Tayyip Erdogan said in an AP report.

Two gunmen from DHKP-C were killed by police when special forces stormed the Istanbul courthouse.

Later in the day, hospital officials said Kiraz had died.

More to follow...