Updated

Internet service has been cut off in Libya for a second consecutive day as protesters step up demonstrations against longtime leader Moammar al-Qaddafi, a U.S. company that monitors Internet traffic said on Saturday.

Massachusetts-based Arbor Networks said data collected from 30 Internet providers around the world showed that online traffic in and out of Libya was disconnected abruptly at 7:15 p.m. EST on Friday (0015 GMT on Saturday) after two partial interruptions earlier that day.

Internet traffic returned several hours later at reduced levels only to drop off completely again at 4:55 p.m. EST on Saturday (2155 GMT), according to the Arbor data.

Dozens of protesters were killed in clashes with Libyan security forces in the eastern city of Benghazi on Saturday, a witness said, in the worst unrest in Qaddafi's four decades in power.

The Internet has been used in recent weeks by anti-government protesters in North Africa and the Middle East to help coordinate their demonstrations.

Egyptian authorities cut Internet service for a few days during a revolt that succeeded last week in toppling Hosni Mubarak after 30 years in power.