Protesters gathered in Athens earlier this week to hold an open-air memorial service for 13 workers killed during round-the-clock construction in preparation for the Olympic games, according to the Associated Press.

About 500 demonstrators stood in silence as the names of the workers were read out and olive wreaths placed on 13 crosses erected outside Greece's parliament.

Deaths at construction sites have spurred a small but vocal anti-Olympics movement in Athens, adding to anger over massive security measures and commercialism surrounding the games.

Construction crews raced round the clock this year to finish off seriously delayed Olympic venues and infrastructure projects, pushing up the Olympic budget to more than $7 billion and compromising worker safety, according to protest and human rights groups.

Amnesty International, the human rights watchdog, said the Olympic death toll could be as high as 40.