Spain's Prime Minister Jose Luis Rodriguez Zapatero (L)prepares to cast his ballot at a polling station in Madrid March 9, 2008. Spain's parliamentary elections kicked off Sunday as voters began to cast their ballots to elect a new Congress and Senate after four years of rule by the socialist government of Prime Minister Jose Luis Rodriguez Zapatero. (Xinhua Photo)

Spanish Prime Minister Jose Luis Rodriguez Zapatero claimed victory in Sunday's parliamentary elections.

Zapatero addressed joyful supporters in Madrid while the rival Popular Party (PP) had conceded defeat.

PP spokesman Pio Garcia Ecudero admitted his party's loss and congratulated Zapatero's Spanish Socialist Workers' Party (PSOE).

With 93.5 percent of the ballots counted by late Sunday night, the PSOE won 43.77 percent of the vote against 40.12 percent for the PP.

With this standing, the PSOE would get 168 seats in the 350-strong lower house of parliament. The PP would get 154 seats.

The PSOE would still fall short of an absolute majority in the house and will need to form a coalition government with regional parties.

The PSOE and the PP won 164 and 148 seats respectively in 2004 elections.