Projections from early counting of votes in Italy's general election show a centre-right grouping led by Silvio Berlusconi slightly ahead in the Senate, a result that could cause deep political instability if confirmed.
The centre-left is ahead in the vote for the lower house, but control of both houses is needed in order to govern.
Mr Berlusconi's aim is to win enough power in the Senate to paralyse a centre-left government.
The other feature of the vote so far is a strong showing by a new anti-establishment movement led by Beppe Grillo, a popular comedian, which has attracted nearly 20% support.
Grillo has ridden a wave of voter anger about both the pain of an austerity programme devised by prime minister Mario Monti and a series of political and corporate scandals