Anti-austerity activists are planning new protests in Athens' main square, where a retiree publicly killed himself leaving a note that blasted politicians over the country's financial crisis.

More than 1,500 people gathered at the spot Wednesday hours after the suicide, chanting slogans and clashing with riot police.

Groups ranging from social media activists to schoolchildren have said they will join in the protests later Thursday.

The 77-year-old retired pharmacist chose the morning rush hour to shoot himself in the head near a subway exit on Syntagma Square _ a focal point for protests and a stone's throw from Parliament.

In the note published by local media, the man said could he not survive on his pension and expected Greeks to take up arms and "hang traitors" in the square.