Hundreds of riot squad officers secured roads around Athens Polytechnic - where the 1973 student uprising began - as helicopters hovered overhead.

At least 44 people were killed when Greece's military government sent tanks to put down the 1973 uprising at Athens Polytechnic.

The events marked the beginning of the end for the government which fell less than a year later.

Extra security was in place outside foreign firms, diplomatic offices, and banks during the march.

Officers found several bags containing petrol bombs hidden near garbage bins in the city centre.

The demonstration came as Greece's ruling conservative government is faced criticism for its tight economic measures. It is trying to get the country's budget deficit below the European Union's ceiling of three per cent of gross domestic product to avoid possible sanctions.

Athens has been crippled by strikes and rallies by state school teachers who are demanding pay rises. Temporary civil servants have also been protesting for permanent jobs.