Turkey Blocks Twitter and YouTube

​Turkish authorities have ordered a ban on YouTube, Twitter, and Facebook on Monday for hosting pictures of an Istanbul prosecutor who was held hostage and later killed last week, according to multip​le re​ports.

Following the order, local Internet Service Providers have started blocking access to Twitter and YouTube, according to Frederic Jacobs, an independent internet security researcher.

Latest network measurement shows block being deployed across all ISPs across the country. — Frederic Jacobs (@FredericJacobs)April 6, 2015

The ban on Facebook was reportedly lifted after the social network complied with the court order to remove the photos, according to the local newspaper Hurryie​t Daily News. According to his network measurements, Jacobs said the block on Facebook appeared to have been effectively lifted.

Data shows block might be reversed for Facebook. Twitter DNS is clearly poisoned for TurkTelecom users. — Frederic Jacobs (@FredericJacobs)April 6, 2015

A Facebook spokesperson confirmed to Motherboard that the social network is not blocked in the country.

"We received valid court orders from the authorities in Turkey requiring us to restrict access to certain content," the spokesperson said. "We have complied, but are appealing."

The authorities reportedly ordered the blocks due to the social networks hosting pictures of Mehmet Selim Kiraz, the prosecutor who was ​held hostage at gunpoint last week by the far-left Revolutionary People's Liberation Party-Front (DHKP-C) militant group. Kiraz died due to several gunshot wounds after authorities stormed the office where he was being held.

"This has to do with the publishing of the prosecutor's picture. What happened in the aftermath (of the prosecutor's killing) is as grim as the incident itself," presidential spokesman Ibrahim Kalin told Reute​rs.

The country-wide blocks of Twitter and YouTube come a year after Turkey caused an international uproar for blocking the same social networks. Last year, Turkey b​loc​ked access to Twitter for roughly t​wo weeks, while YouTube was block​ed for 67 d​ays.

The current block seems to be done via the Domain Name System (DNS), Jacobs told Motherboard.

"It's boring stuff, really. Just a dumb DNS block. Poorly executed," Jacobs said. "Boring because deja-vu."

The DNS is basically a phone book for the web. To block sites this way, ISPs "add a rule to the configuration of the DNS server software to return a specific entry instead of resolving it like it usually does," Jacobs explained. So when someone types Twitter.com, for example, the ISP shows another site instead of the one the user is actually requesting.

Last year, Turkish users found ways around this kind of block, including spreading alternative DNS addresses on streets' g​raffiti.

A YouTube spokesperson told Motherboard that the company is aware of the reports, and is "working to restore the service for users as soon as possible."

Twitter did not answer to Motherboard's request for comment but posted a similarly-worded announcement on its @Policy account.

We are aware of reports of interruption of our service in — Policy (@policy)April 6, 2015

Deniz Ergurel, a tech reporter at th English-language daily Today's Zaman shared with Motherboard screenshots of how Twitter looks like inside of Turkey after the block.

This is how the Twitter app looks like inside of Turkey.

— Lorenzo Franceschi B (@lorenzoFB)April 6, 2015

UPDATE 06/04/2015, 10:34 a.m. ET: This story has been updated to add YouTube's,  Twitter and Facebook comments and a screenshot of Twitter's app.