"Spain cannot substitute for the International Criminal Court," Javier Zaragoza, the chief prosecutor at the National Court, the country’s top criminal court, told AFP at his office in central Madrid.

Spain has since 2005 been one of a handful of countries to operate under the principle of "universal jurisdiction", a doctrine that allows this court to reach beyond national borders in cases of torture, terrorism or war crimes, even if there are no Spanish victims.

The National Court currently has 13 cases open involving genocide or crimes against humanity affecting eight countries: China, Israel, the United States, Guatemala, El Salvador, Rwanda, Morocco and Germany, where the case involves alleged Nazis.

One of the cases in the US involves allegations of torture at the Guantanamo Bay detention camp in Cuba, while another under study could lead Spanish judges to probe six former officials of the administration of George W Bush.

"The principle of universal jurisdiction, which was an advance against impunity, is turning into a problem. It is being used to open investigations against other countries which have opened their own investigations for the same facts," said Zaragoza.

He was referring to a National Court judge’s decision to go ahead with a probe into alleged crimes against humanity by top Israeli military figures over an air force bombing in Gaza in 2002 that killed 15 people, a move which was opposed by Spanish public prosecutors.

The complaint was lodged at the court by the Palestinian Centre for Human Rights against former Israeli defence minister Benjamin Ben-Eliezer and six senior military officials, sparking strong objections from Israel.

Zaragoza said the National Court should take into account the fact that the Israeli Supreme Court had already ordered an investigation into the bombing.

"We cannot call into question the Israeli Supreme Court," he said.

Last week Israel’s foreign ministry spokesman Yigal Palmor dismissed the judge’s decision to push on with the investigation as "a cynical and baseless political manoeuvre."

China also criticised a request by a National Court judge to question eight Chinese leaders as official suspects in a case of genocide in connection with a crackdown on unrest that erupted in Tibet in March 2008.

"We urge relevant countries to observe international law and fundamental norms governing international relations, and not to encourage separatist forces," Chinese foreign ministry spokesman Ma Zhaoxu told reporters last week.

Carlos Divar, the president of the body that oversees Spain’s judiciary, has also called for judicial restraint in the use of the principle of universal jurisdiction.

"We cannot become the judicial police of the world," he said, adding that "Spain cannot live in permanent diplomatic conflict".

But a National Court judge said investigations cannot be stopped because of diplomatic pressure. "We are only applying the law," he told AFP.

Zaragoza said the Spanish government will likely agree to a legal reform which will limit the application of the principle of universal jurisdiction much like Belgium did six years ago.

Under pressure from the United States and Israel, Brussels in 2003 altered a decade-old law of universal jurisdiction, which was similar to Spain’s, to allow judges to open probes only in cases where there is a link to Belgium.

Pierre Ausseill/AFP/Expatica