Greece's two main parties, which back tough austerity measures, have lost their parliamentary majority, throwing the country into political uncertainty, BBC News reported.

Pasok and New Democracy attracted less than a third of the vote in elections on Sunday, May 6.

With about 99% of votes counted, center-right New Democracy (ND) is leading with 18.9%, down from 33.5% in 2009.

ND and the socialist Pasok have between them run Greece since the 1970s. Since November, they have been in a coalition led by technocrat Prime Minister Lucas Papademos.

Pasok could only manage third place with 13.2%, down from 43.9% in the last elections and behind Syriza, which polled 16.7% and opposes the government's austerity measures.The neo-Nazi Golden Dawn party, with almost 7% of the vote, is on course for at least 20 seats in parliament.

There is widespread anger across Greece to harsh measures imposed by the government in return for international bailouts.