Access was restricted in Turkey on Friday to Facebook Inc (FB.O), Twitter Inc (TWTR.N) and Alphabet Inc's (GOOGL.O) YouTube shortly after news that a military coup was under way, according to two internet monitoring groups.
Turkey Blocks, a group that monitors internet shutdowns in the country, and Dyn, which monitors internet performance and traffic globally, both reported it was difficult or impossible to access social media services in Turkey.
Turkey's military said on Friday it had seized power, but the prime minister said the attempted coup would be put down.
The Turkish government under President Tayyip Erdogan has repeatedly moved to block social media in periods of crisis and political uncertainty. It was not immediately clear whether the government or another actor ordered the block late Friday.
The government normally implements its internet restrictions through orders to Turkey's main internet service providers.