In what's become a familiar pattern in recent years, the government in Iraq appears to have ordered major Internet shutdowns over the past few days amid escalating sectarian violence in the country.

Internet monitoring firm Renesys on Friday said it observed two significant outages this week affecting customers of Earthlink and IQNetworks, the two largest Internet Service Providers (ISPs) in Iraq. In each case, the outages lasted between two and three hours, Renesys said.

The outages appear to be government directed and timed to coincide with military operations in the country, Renesys said in a blog post Friday.

The company said it has also received credible reports that the Iraqi government is blocking specific services like Facebook and Twitter.

The tactics are the same as those used by other governments recently, including Turkey, and appear to be an attempt to choke off or compromise some services while keeping others online.

"This tactic, of 'moving up the stack' to shut down particular Web services at the local provider level mirrors the evolution toward more technically subtle partial Internet shutdowns" adopted in other countries, Renesys noted.

In Turkey, for instance, TurkishTelecom hijacked the IP address space of public DNS resolvers belonging to companies like Google in order to surreptitiously redirect users from inside the country to alternate servers.

The same DNS tampering is being done in Iraq, as well, Doug Madory, an analyst at Renesys said in emailed comments to Computerworld. "The government is likely finding that they also need Internet access to conduct their business, so cutting it all off may hurt them, as well."

The government appears to have also realized that a wholesale Internet blockage will only serve to antagonize its citizens.

"By attempting to surgically go after the websites that concern them, it allows other normal Internet communications to proceed. This may be the rationale used by the Ministry of Communications in issuing these blocks," Madory said.