The leader of Spain's Socialists, Pedro Sanchez, said Wednesday his party will not back acting Prime Minister Mariano Rajoy's bid to form a new government following an inclusive weekend election.

"We were clear: we will vote against the continuity of the Popular Party at the helm of the government, with Mariano Rajoy as prime minister," he told a news conference after holding talks with Rajoy for the first time since Sunday's election.