Thousands of people demonstrated in Athens on Thursday in a yearly protest marking the anniversary of a deadly crackdown on a 1973 student revolt against a US-backed junta. Some 5,500 people were marching in the capital, police said, in a demonstration closely watched by security forces, as violence often breaks out on the sidelines. Police had earlier said 5,700 officers were deployed in Athens for the day, backed by drones, a helicopter and water cannon. Much of the city centre was closed off to traffic and central Athens subway stations closed early.