An Eritrean man carrying a canister of liquid tried to force his way into the cockpit of a Qatari Airways flight Thursday, screaming at flight attendants before he was restrained, airport officials said. The plane, en route to Doha, Qatar, from Amman, returned safely to the Jordanian capital. It was not immediately known what liquid was in the canister, security officials at Amman airport said. The man was detained once the plane landed in the Jordanian capital, and security officials were investigating whether the man had any associates with him on the flight, the officials said. The incident came hours after Great Britain announced it had foiled a major terror plot to blow up airplanes headed to the United States from London's Heathrow Airport. US Homeland Security Secretary Michael Chertoff said the terrorists planned to use liquid explosives disguised as beverages and other common products and set them off with detonators disguised as electronic devices.