By Andrei Khalip


LISBON (Reuters) - Portugal on Thursday asked Iraq to waive the diplomatic immunity of the twin sons of its ambassador after prosecutors sought their interrogation as formal suspects in the beating of a local youth who ended up in intensive care.


The case, which risks escalating into a diplomatic row, caused an uproar in Portugal after the two 17-year-olds, who have acknowledged their part in the beating of 15-year-old Ruben Cavaco on Aug. 17, were swiftly released by police on the night of the incident.


The foreign ministry said on Thursday that it had handed the request to the Iraqi embassy's charge d'affaires, and now awaited a response from the Iraqi authorities. Ambassador Saad Mohammed Ridha traveled to Baghdad on Tuesday.


As family members of a diplomat the twins are protected from prosecution in the host country under international convention on diplomatic relations.


The prosecutor general's office said in a statement earlier that it asked the foreign ministry to intervene after the investigation pointed to "facts that could potentially constitute the crime of attempted manslaughter".

"With the pieces of evidence already collected and the investigation carried out so far, it is considered essential that the two suspects with diplomatic immunity be interrogated as formal suspects in order to clarify the facts," it said.

The incident took place in Ponte de Sor in central Portugal where one of the brother is attending flying school.

In an early statement the Iraqi embassy said the brothers, Haider and Ridha, had acted in self-defense and their attackers had shouted racist and anti-Muslim slurs, though the brothers themselves in later comments to media did not repeat this.

They told SIC television channel on Monday they had first been attacked by a group of young men, including Cavaco, after a night of drinking at a bar. They said they were later confronted once more by Cavaco which is when they beat him.

The brothers apologized to Cavaco and his family but said they were all "victims of circumstance" and that the media had exaggerated the case. After several days in a drug induced coma, Cavaco left intensive care unit on Tuesday.

It is only possible for a diplomat's home country to waive immunity, but such cases are rare. Portugal can expel a diplomat or his family, but cannot question or detain the suspects. If Iraq refuses to waive immunity, it could still prosecute the two at home, if it so chooses.

(Reporting By Andrei Khalip; Editing by Richard Balmforth)