Spain's new Socialist leader vowed Monday to bring home the 1,300 Spanish troops now in Iraq, a move that follows the worst terrorist attack ever to hit the U.S. ally.
"The military intervention was a political error for the international order, for the search for cooperation, for the defense of the United States," Jose Luis Rodriguez Zapatero (search) told reporters, adding that Spain would maintain "cordial" relations with Washington.
"It divided more than it united, there were no reasons for it, time has shown that the arguments for it lacked credibility and the occupation has been managed badly."
Although Zapatero did not say exactly when the troops would come home, he did reaffirm his pledge that they would be recalled by June 30 unless the United Nations (search) assumes control of multinational military operations in Iraq.
U.S. authorities said Monday they believe Al Qaeda (search) had a role in the Madrid train bombings, which killed 200 people and wounded some 1,500.
Police also were investigating a possible link between the bombings and attacks in Casablanca last year, focusing on a Moroccan arrested in Spain over the weekend, a Moroccan official told The Associated Press.
Zapatero's Socialists delivered a surprise defeat to Prime Minister Jose Maria Aznar's (search) conservatives on Sunday. Aznar was a major supporter of President Bush's war on terror and committed troops to the war in Iraq at a time when most European nations stayed out.
The election came amid charges that Aznar made Spain a target for terrorists by supporting the war, and that his government concealed possible connections between the attack and Islamic terrorists for political gain.
Bush called Zapatero to congratulate him on his victory. "The two leaders said they both looked forward to working together, particularly on our shared commitment to fighting terrorism," White House spokesman Scott McClellan said.
View From the United States
Some American lawmakers hope that because of Zapatero's comments about a U.N. role, he is setting the stage for a possible change of opinion and will instead keep Spanish troops in place.
"It appears to me that the new government coming in says they'll withhold judgment," Sen. Richard Lugar, R-Ind., chairman of the Senate Foreign Relations Committee, told reporters. "Our hope would be that they continue to participate vigorously."
U.S. Secretary of State Colin Powell (search) said on "Fox News Sunday" that he saw a clear opportunity to get a U.N. mandate.
"Look at how much we've accomplished," Powell said. "We now have an administrative law that has been passed by the Iraqi Governing Council which gives the Iraqi people for the first time a bill of rights. It puts in place an independent judiciary."
But some analysts saw Zapatero's move as a direct slap at the United States.
"It's a terrible message to send. It's very divisive," David Gergen, former communications adviser to several U.S. presidents, told Fox News. "This weakens U.S. policy in trying to bring unity to the West as we try and fight terrorism."
Lawrence S. Eagleburger, secretary of state under President George H.W. Bush, expressed concern that U.S. allies who get hit badly enough by terrorists might jump ship. But he noted that Spain hasn't done so yet.
"I doubt that the rest -- that the countries we have with us now will really cut and run, and the Spanish haven't doone that yet either," he said.
In Sunday's election, the Socialists defeated Aznar's ruling Popular Party, jumping from 125 seats to 164 in the 350-member Congress of Deputies. The conservatives fell from 183 to 148.
"Aznar was like (British Prime Minister) Tony Blair for us. He was a stout ally. To have him soundly defeated at the polls was a big setback for us," Gergen said.
Leaving the door slightly open for a continued Spanish presence in Iraq, Zapatero said a stronger U.N. role in Iraq could change his opinion.
"I have said clearly in recent months that unless there is a change in that the United Nations take control and the occupiers give up political control, the Spanish troops will come back, and the limit for their presence there is June 30," he said.
Socialist Leader Vows Terror Fight Will Continue
The train bombings were followed by nationwide street rallies against the attacks, smaller ones against Aznar's government.
Five suspects, including three Moroccans, were arrested and Al Qaeda reportedly claimed responsibility in a videotape.
The tape raised the possibility that terrorists aligned with Usama bin Laden had changed the course of a national election. Spain's government has insisted its prime suspect in Thursday's rail bombings was the armed Basque separatist group ETA.
Late Sunday, Zapatero started his victory speech by remembering those killed in the railway bombings.
"At this moment I think of the lives that were broken by terror on Thursday," he said, then asked the crowd to join him in a minute of silence.
"My most immediate priority will be to fight terrorism," he said. The Spanish Socialist Workers Party ruled from 1982 to 1996 but ran afoul of corruption scandals and was voted out in 1996, when Aznar took power.
Aznar chose not to seek a third term, saying he wanted renewal in government and his party.
Zapatero said Monday he would attempt to form a purely Socialist government, not a coalition with other parties. The Spanish stock market shuddered over the news that the Socialists will take power, with the benchmark Ibex-35 stock index dropping 2.4 percent at the opening bell. It was down 3.2 percent shortly after noon local time.
The Associated Press contributed to this report.