When asked during a radio interview what he would do if U.S. President Bush asked him to reconsider his position, prime minister-elect Jose Luis Rodriguez Zapatero said: "I will listen to Mr. Bush but my position is very clear and very firm."
Zapatero's Socialists were the surprise winners in weekend elections, which saw the Popular Party, a U.S. ally in Iraq, being defeated. That followed last week's multiple bombings in Madrid that killed some 200 people.
In Tuesday's interview to Onda Cero radio, Zapatero also labeled the occupation of Iraq a "fiasco."
The new leader called for better ways to combat terror.
"Fighting terrorism with bombs ... with Tomahawk missiles, isn't the way to defeat terrorism," he said. "Terrorism is combated by the state of law."
Spain has some 1,300 troops in Iraq. Zapatero has said he will pull back the troops by June 30 unless the United Nations authorizes a multinational force.