May Day, which falls on May 1, is observed in many countries to celebrate workers` rights

May Day events have also given many an opportunity to air general economic grievances or political demands

In the Philippine capital, Manila, hundreds of workers and left-wing activists marched together 

They held a rally in the scorching summer heat to demand wage increases and job security amid soaring food and oil prices

Riot police stopped the protesting workers from getting close to the presidential palace

Waving red flags and holding up posters that read: `We work to live, not to die` and `Lower prices, increase salaries`

The protesters rallied in the street, where they chanted and delivered speeches about the difficulties faced by Filipino labourers