Organisers of a U.N. conference on global telecommunications say hackers apparently blocked one of its main websites and caused disruptions in the talks that some critics fear could lead to greater controls over the Internet.

The U.N.’s International Telecommunications Union says the website was hit late on Wednesday, blocking access to its main page and interfering with a closed-door working group. It says it’s still investigating but initial signs point to hackers.

Internet traffic was diverted to a backup website for two hours. The 11-day gathering in Dubai is being closely watched for possible new international pacts on Internet commerce and security.

The U.S. is leading efforts to block new Internet regulations, fearing they could open the door to greater monitoring and restrictions.