Milan magistrates suspect a CIA team grabbed Hassan Mustafa Osama Nasr off a Milan street and flew him for interrogation to Egypt, where he said he was tortured.
A European Union warrant is automatically valid across the 25-nation bloc and does not require approval of any government.
The warrant was agreed by the European Union in the wake of the September 11 attacks on the United States in 2001 and was hailed as a key part of the bloc's fight against terrorism.
Prosecutor Spataro told Reuters he had also asked Interpol to try to detain the suspects anywhere in the world.
Prosecutors had asked the Italian justice ministry last month to seek the extradition of the suspects from the United States, but Justice Minister Roberto Castelli has not yet decided whether to act on the request.
Earlier this week, Italian Prime Minister Silvio Berlusconi said he did not believe CIA agents had kidnapped Nasr, but added that governments were not going to defeat terrorism by playing by the rules.
Justice officials believe Nasr, also known as Abu Omar, is still in custody in Egypt. Italian investigators have accused him of ties to al-Qaeda and recruiting combatants for Iraq, and a Milan judge has issued a warrant for his arrest.
There has been a series of investigations into whether US intelligence officials used Europe as a hub to illegally transfer militant suspects to third countries for interrogation.
Secret Polish report
The Polish government has decided not to make public the results of an inquiry into the possible existence of American CIA prisons on Polish soil, a spokesman said.
"The report should not be made public," spokesman Jan Dziedziczak told AFP, refusing to give details and saying that the matter was considered closed by the authorities.
"The minister with responsibility for the intelligence services, Zbigniew Wassermann, submitted the results of the inquiry to the supervisory parliamentary commission," he said.
"All the members of the commission said they were satisfied with his explanations and considered the matter closed."
Polish Prime Minister Kazimierz Marcinkiewicz had promised last week that the results of the probe would be made known in a comprehensive fashion.
"We must probe this affair to its very depths because it does not foster a situation of security in Poland," Mr Marcinkiewicz told reporters on December 12.
The US television network, ABC, said earlier that the United States had detained eight senior members of the Al-Qaeda network in Poland on unspecified dates.
It also claimed that the CIA had evacuated all suspects to north Africa in recent weeks since the row broke out.
On December 9, the Gazeta Wyborcza paper quoted Marc Garlasco of the US body, Human Rights Watch, as saying Poland housed the CIA's main European base for the interrogation of terror suspects, and that local authorities must have known.