Iraq widened a clampdown on social media on Monday, blocking secure private communications channels to prevent Sunni militants from using them in their stunning sweep that is threatening to dismember the country.
In addition to banning virtual private networks (VPNs), it has also recently instructed mobile telephone operators to stop mobile data including instant messaging services, a mobile operator and an industry source said on Monday.
Sunni armed groups led by the Islamic State of Iraq and the Levant (ISIL) routed Baghdad's army last week, seizing Mosul and much of the north of the country and also vowing to push onto the capital.
These setbacks led state-run Iraq Telecommunications and Post Company (ITPC), which owns almost all fixed line networks outside Kurdistan, to block some social media including Facebook, Twitter, Whatsapp and Skype, according to a circular obtained by Reuters.
That spurred many Iraqis to access these applications through VPNs, which are now blocked, Martin Frank, chief executive of Sulaymaniyah-based Internet provider IQ Networks, told Reuters.
VPNs allow the user to appear as if they are accessing the Internet from elsewhere. Banning them may be ineffective because tech-savvy users can usually find alternative means.
The government has instructed mobile operators Zain Iraq, part of Kuwait's Zain, Ooredoo unit Asiacell and Orange affiliate Korek to block mobile data, a Korek spokeswoman and an industry source said on Monday.
Mobile calls and texts have not been disrupted, they said.
"The government's ability to implement Internet blocks, targeted or total, is fairly piecemeal," said Doug Madory, a senior analyst at Renesys, a US-based firm that carries out real-time analysis of internet routes and traffic.
"Internet providers in the north or who have transit from internet providers in the north are less likely to experience blocking."
The ITPC circular last week also ordered a complete Internet shut down in Kirkuk, Salaheddin, Anbar, Diyala and Nineveh provinces as well as some districts and towns around Baghdad including Abu Ghraib and Fallujah,
The Internet briefly went down in parts of Baghdad on Monday, according to Renesys.
Monday's fleeting shut down followed earlier, wider blocks. On June 9, the day before Mosul - Iraq's second largest city - fell to ISIL, around 43 percent of Iraq's networks were offline for a few hours. Satellite and routes to Turkey mostly provided the remaining connectivity.
"These interruptions appear to coincide with military operations, amid concerns that ISIL forces are using Internet websites to coordinate their attacks," Renesys wrote.
Excluding Kurdistan, "all services were down at that time in Baghdad and the cities controlled by central government," said IQ Networks' Frank.
The Internet failed again on June 12. This outage lasted more than three hours, although Frank said this was due to a combination of fibre cuts and equipment failures rather than a government order.
Iraq has yet to allow 3G services and only basic websites and services are available over 2G.