A fire at Tehran’s main telecommunications building disrupted internet services on Friday, Iran’s communications ministry said.

It said the fire was caused by a malfunction in a power connection.

“A minor internet outage that occurred today in some areas of Tehran due to a power outage led to a fire at the LCT centre, which was quickly rectified and the backup system was quickly replaced,” ministry spokesperson Mahdi Salem wrote on Twitter.

The ministry said the nearby city of Karaj was also affected by the outage.

Iran has some of the strictest controls on internet access in the world, but its blocks on US-based social media such as Facebook, Twitter and YouTube are routinely bypassed by tech-savvy Iranians using virtual private networks (VPNs).

A new bill introduced in parliament last month would further restrict government control over the internet if approved.