In a five-minute telephone call initiated by Zapatero, Bush "expressed his regret to president Zapatero about the decision to abruptly announce the pullout of Spanish troops from Iraq", said Whitehouse spokesman Scott McClellan on Monday.
"The president urged that the Spanish withdrawal take place in a coordinated manner that does not put at risk other coalition forces in Iraq," McClellan told reporters.
The president stressed the importance of carefully considering future actions to avoid giving false comfort to terrorists or enemies of freedom in Iraq," the spokesman said.
Other nations to follow
Meanwhile, the United States is expecting other nations with forces in Iraq to reassess their position following Spain's decision.
Condoleezza Rice, speaking on ABC's This Week before the
decision was announced in Madrid, said, "We know that there are others who are going to have to assess how they see the risk.
“We have 34 countries with forces on the ground. I think
there are going to be some changes," Rice added.
Spain, along with Britain and Italy, had been one of the
strongest supporters of Bush's invasion of Iraq last year to
oust President Saddam Hussein.
However, Portugal announced it would keep its national guards in Iraq despite Spain's vow.
"Portugal has adopted a position [in relation to Iraq] and it is not going to change," Prime Minister Jose Manuel Durao Barroso told reporters. "Our position is to not give any signal which can encourage international terrorism," he added.
Portugal's left-wing opposition parties have stepped up their pressure on Durao Barroso to withdraw the country's 128 national guards from Iraq since Zapatero's election win in Spain last month.
Nearly three in four Portuguese want the national guards to be withdrawn, a poll said last month.