Spain is facing growing calls to limit the scope that its judges have to investigate alleged human rights abuses in other countries. The criticism comes after recent cases caused diplomatic tensions with China and Israel.

Spain is one of a few countries to operate under the principle of "universal jurisdiction", a doctrine that allows its courts to reach beyond national borders in cases of torture, terrorism or war crimes, even if there are no Spanish victims.

The Spanish 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.

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.

But "Spain cannot substitute for the International Criminal Court," Javier Zaragoza, chief prosecutor at Spain's National Court, told AFP.

"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.

Zaragoza was referring to a National Court judge's decision to probe alleged crimes against humanity by top Israeli military figures over a 2002 air force bombing in Gaza that killed 15 people.

"The National Court should take into account the fact that the Israeli Supreme Court had already ordered an investigation into the bombing," says Zaragoza, adding, "we cannot call into question the Israeli Supreme Court."

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

Police of the world

Carlos Divar, president of the body that oversees Spain's judiciary, has 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, "Spain cannot live in permanent diplomatic conflict".

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.