By Magda Panoutsopoulou

ATHENS

Greeks started to vote in the country's general elections Sunday to elect a new government and parliament.

The latest opinion polls show leftist opposition Syriza Party ahead of the ruling center-right New Democracy Party by at least 5 percent.

European leaders eye the results fo the elections closely as a Syriza victory may generate a clash with the Troika -- the EU, European Central Bank and the IMF -- which could possibly start a new crisis between the nation and its creditors, with the euro in the balance.

Alexis Tsipras, the leader of Syriza, has promised to form an anti-bailout government.

Early national elections were triggered as Prime Minister Antonis Samaras' presidential candidate Stavros Dimas did not gain the required support of the lawmakers in December 2013. 

Samaras was forced to call for snap elections. 

Polls close at 19.00 local time (1700 GMT). First estimates are expected at 21:30 local time.

The voting started at 7:00 a.m. local time (0500 GMT).

The electoral body is made up of 9,808,760 registered voters who are supposed to cast their vote at the 19,449 polling stations across the country.

18 political parties and four coalitions seek the Greeks' votes. 

- Greek electoral system 

The party with the majority of votes automatically wins a 50 seat premium in order to form a stable government.

If the first party doesn't have enough seats to form a government, President Karolos Papoulias will give the leader of the first-place party a mandate to form a coalition.