A Turkish prosecutor has ordered Internet providers to block social networking sites, including Twitter and YouTube, a spokesman for President Recep Tayyip Erdogan said Monday.

The request stems from postings of photos that show militant Marxists pointing a gun at a prosecutor who died last week in a shootout between police and the Marxists who were holding him hostage.

Government officials have blasted Turkish media for posting the images, which they have called anti-government propaganda. The prosecutor, Mehmet Selim Kiraz, was shot in the head during the standoff and died in a hospital soon after.

It was not immediately clear how the social media order was being carried out, but the government-run Anadolu Agency quoted the Union of Internet Providers as confirming that access to Twitter and YouTube has been blocked. Some users could still access the sites, while others reported being blocked.

The agency said access was blocked because Twitter and YouTube did not remove images of the prosecutor despite an official notification. It says the Internet Providers notified Twitter and YouTube, but video, photographs and audio continued to be posted on these sites. The Turkish telecommunications authority would not immediately comment.

Last year, Turkey blocked access to YouTube and Twitter after audio recordings of a secret security meeting or tapes suggesting corruption by government officials were leaked on the social media sites. Turkey's highest court, however, overturned the bans, deeming them to be unconstitutional.

Previous moves by Turkish authorities to block the social media networks have provoked widespread criticism by Western governments and human rights organizations.

Many tech-savvy users, including Erdogan ally President Abdullah Gul, found ways to circumvent the bans both on Twitter and YouTube while they were in place.