The watchdog made the clarification after Twitter users complained they were unable to access the micro-blogging site for nearly two hours Monday.
“There is no prevention on access to Twitter in the country,” the Information and Communication Technologies Authority said in a statement.
However, the watchdog acknowledged it received some complaints from users of Turkcell, Turkey’s largest operator, who said they were unable to access the popular micro blogging site for two hours.
"An investigation into the allegations has started and an investigator from the authority has been sent to Turkcell," the statement added.
Earlier this year, Turkey had blocked Twitter for a brief period over the company’s alleged refusal to remove some Web links.