A Turkish prosecutor who had been held captive by a banned leftist group for nearly six-hours has died as a result of wounds sustained during the standoff, which ended in a firefight with authorities.

“He was dead when he arrived at the hospital we tried our best but we failed to save him,” an official from the Florence Nightingale hospital in Istanbul told CNN Turk, in reference to prosecutor Mehmet Selim Kiraz.

Kiraz was rushed there with severe injuries after security forces launched an operation to free him from his two captors at an Istanbul courthouse. The two hostage-takers were killed in the raid.

The confirmation of Kiraz's death was a tragic end to the incident that began earlier that day when two members from Marxist-Leninist Turkish group the Revolutionary People's Liberation Party-Front (DHKP-C) took the prosecutor hostage.

Prior to the confirmed deaths, several gunshots and at least two explosions were heard, as smoke rose from the courthouse’s upper floor.

Earlier in the day, DHKP-C published a picture of Kiraz with a gun to his head, threatening he would be killed at 12:36 p.m. GMT, three hours after gunmen stormed his office, unless its demands were met.

Kiraz is leading an investigation into the death last March of 15-year-old Berkin Elvan, who died after nine months in a coma from a head wound sustained during anti-government protests.

The DHKP-C demanded that the police officer it blames for Elvan's death confess on television, the other officers involved be tried in “people's courts” and charges against those who attended protests for Elvan be dropped.

In a brief video message on a widely followed Twitter account describing itself as that of Elvan's family, his father appeared to call on the group not to harm the prosecutor.

“We want justice. We don't want anyone to shed even a drop of blood. We don't want other mothers to cry,” Sami Elvan said.

Earlier, Prime Minister Ahmet Davutoglu met with current and former interior justice ministers at the ruling AK Party headquarters in Ankara to discuss the hostage crisis, officials in his office said.

Television footage showed special forces officers entering the courthouse and officials being escorted out. Armed police officers, many wearing flak jackets, surrounded the building and fire engines were positioned outside.

DHKP-C was behind a suicide bombing at the U.S. Embassy in 2013. In 2001, two policemen and an Australian tourist died in a DHKP-C attack in central Istanbul.

Al Jazeera and wire services