DUSHANBE, Tajikistan -- The Central Asian nation of Tajikistan has blocked social media website Facebook for the third time in twelve months.

Also blocked Thursday was the U.S Congress-funded Radio Free Europe/Radio Liberty's Tajik language service. Internet service providers say they denied access to the sites at the request of communications authorities.

Tajikistan has low levels of Internet penetration, but Internet regulation in the authoritarian former Soviet republic is nonetheless expected to be strict ahead of November's presidential election.

Emomali Rakhmon has ruled the impoverished country for two decades and expected to easily retain power, but officials remain nervous of any signs of opposition to the government.