Tens of thousands of people have been evacuated from the German city of Frankfurt after construction workers discovered a huge unexploded bomb dating from World War Two.

Authorities are currently working to defuse the 1.8 tonne bomb, which was dropped on the city by British air forces.

Some 60,000 people were ordered to leave their homes, including care home residents and hospital patients.

Police set up a 1.5-kilometer cordon around the bomb before starting work to defuse it.

Police said they had removed the bomb's main detonator on Sunday afternoon, but the explosive had not yet been fully made safe.

Unexplored bombs are still regularly discovered in Germany, 72 years after the war ended.

About 20,000 people were evacuated from the western city of Koblenz before specialists disarmed a 500-kilogram US bomb on Saturday.