The Greeks will elect a new parliament on May 21st. A second ballot - which will most likely be necessary due to a change in the electoral law - could then take place on June 2, Prime Minister Kyriakos Mitsotakis said in a speech at the start of a cabinet meeting that was broadcast by state television.

Mitsotakis' conservative governing party, Nea Dimokratia, is ahead of the main opposition party, the left-wing Syriza, in polls. However, the Conservatives lost votes four weeks ago after the serious train accident that killed 57 people.

Party leader Mitsotakis himself, on the other hand, is more popular with voters - 39 percent want the conservatives to remain head of government in the future, as current polls show. The left opponent, Syriza boss Alexis Tsipras, comes to 32 percent.