The internet was disrupted on Friday due to a fire at Tehran’s main telecoms building, according to Iran’s communications ministry.

According to the report, the fire was started by a faulty power connection.

“A brief internet outage that happened today in some districts of Tehran due to a power loss resulted in a fire at the LCT center, which was promptly rectified and the backup system was quickly replaced,” ministry spokesperson Mahdi Salem tweeted.

The outage also impacted the neighbouring city of Karaj, according to the ministry.

Iran has some of the toughest internet access controls in the world, but its blocks on US-based social media sites like Facebook, Twitter, and YouTube are routinely circumvented by tech-savvy Iranians who use virtual private networks (VPNs).

If passed, a new bill tabled in parliament last month will tighten government control over the internet even more.