Fiber optics from Pakistan Telecommunication Co. Ltd. (PTCL) caused a massive internet blackout across the country last week.

Internet speed across Pakistan plummeted by nearly 60 percent when a major technical issue surfaced in Karachi and Balochistan. The damage affected PTCL and its sister company Ufone, with users experiencing service outages in various parts of Pakistan. PTCL acts as the internet gateway to Pakistan, providing bandwidth to local internet service providers. The main cities affected included Karachi, Lahore, Islamabad and several others.

The main disruptions included PTCL landline, DSL and Ufone cellular services. The exact number of impacted users is still not known. TWA and PTCL are connected with four undersea fiber optic cables that include I-ME-WE, SEA-ME-WE-3, SEA-ME-WE-4 and TWA-1. The country’s internet traffic is currently running on SEA-ME-WE-3 and TWA-1 and catering to the entire telecommunications network.