Istanbul, April 1 (IANS): Three assailants of a banned leftist group who had taken a Turkish prosecutor hostage were killed and the captive freed by the police on Tuesday, according to media reports.

However, the hostage, identified as prosecutor Mehmet Selim Kiraz, was injured, and was transferred to a hospital, Spanish news agency Efe reported citing Turkish daily Sabah.

The members of the Revolutionary People's Liberation Party-Front (DHKP-C) had taken Kiraz hostage at Istanbul's Palace of Justice, which was inaugurated in 2011 as Europe's largest courthouse.

A photo showing a person pointing a gun at Kiraz against the backdrop of the outlawed organisation's flag was posted on social media websites, Hurriyet Daily News had reported earlier.

According to the daily, Kiraz is investigating the death of 14-year-old Berkin Elvan on March 11, 2014, 269 days after he was sent into a coma, struck by a tear-gas canister during a protest in Istanbul. The incident had sparked a wave of indignation in the country.

The militants had demanded that the police officers suspected of killing the teenager should be made to confess their "crime" and prosecuted.

They had also demanded the acquittal of all people being tried for participation in solidarity rallies for Elvan, according to reports.