A Spanish judge has opened a probe into a melee in which Iraqi security forces are accused of killing 11 members of an Iranian exile group in a camp in Iraq in 2009, according to a court order obtained Tuesday by The Associated Press.

Judge Fernando Andreu, saying he is investigating possible crimes against humanity, called on Iraqi Lt. Gen. Abdol Hossein al Shemmari to appear March 8 before the National Court in Madrid to answer questions about the incident. The writ said Shemmari directed the attack on the camp.

In the document, Andreu said Spain was probing the issue because the court viewed as insufficient Iraq's claim that it was investigating. The judge had asked Iraq in December if it was investigating the case.

Under Spain's universal justice doctrine, grave crimes alleged to have been committed in other countries can be prosecuted here under certain conditions, such as when the country where a crime allegedly took place is not investigating.

A new condition laid down recently is that there should be a link to Spain. However, Spanish judges can still act if the crime violates an international treaty signed by Spain. Andreu said that in this case the Geneva Convention applies, as it addresses the protection of civilians in wartime.

The attack by Iraqi troops and police took place July 28 in Camp Ashraf, the base of the Iranian opposition group. Eleven Iranians were killed and 36 were arrested, according to members of the exile group.

The complaint was filed in the Spanish court by human rights lawyers in Spain representing members of the group, the People's Mujahedeen Organization of Iran.

It was not immediately possible to get comment from Iraqi officials.

This is the first universal justice case taken on by the National Court since Parliament narrowed the scope of the law in October 2009 amid criticism from Spain's allies that it was acting like a global policeman — and after angry complaints from some countries that were being investigated, such as Israel and China.

Spain's observance of universal justice became famous in 1998 when Judge Baltasar Garzon had former Chilean ruler Augusto Pinochet arrested in London and sought, ultimately in vain, to put him on trial in Madrid on charges of torture, terrorism and other offenses allegedly committed during his dictatorship.

In 2003, Garzon used the doctrine to indict Osama bin Laden for the Sept. 11, 2001, terrorist attacks in the United States. However, extraditions and convictions under the Spanish procedure have been extremely rare.

The U.S. military had guarded the Ashraf camp since the fall of Saddam Hussein in 2003, under an agreement that made its 3,400 residents "protected persons" under the Geneva Convention. The U.S. military stopped observing the agreement after a new security accord with the Baghdad government took effect in January 2009.

During the attack, American soldiers stood by. U.S officials said they had no authority to intervene.