CAIRO, Aug 1 (Aswat Masriya) - The shooting and killing of nine Muslim Brotherhood leaders during a security raid last month "could qualify as extrajudicial executions", international group Human Rights Watch said in a report on Friday.

"If these were extrajudicial executions, it would signal a new level of lawlessness on the part of Egyptian security forces," said Joe Stork, the group's deputy Middle East director. "As more information emerges, it is clear that the authorities have a lot of explaining to do as to how and why their forces killed nine men on July 1."

On July 1, Egypt's Interior Ministry announced the death of the nine leaders in a security raid on an apartment in Cairo's October 6 suburb, saying they were holding a meeting to discuss "plots" to carry out "terrorist" attacks. It accused them of shooting at the police as the apartment was raided. 

However, Muslim Brotherhood spokesman Mohamed Montaser said the leaders who were killed were "unarmed", adding that the reports on clashes with security forces are "lies".

Human Rights Watch said it spoke to 11 relatives and other witnesses who said the nine men were arrested, fingerprinted and tortured before security forces killed them.

The group said this was the first time it documented "an incident where security forces appear to have deliberately targeted a group of Brotherhood members with lethal violence outside the context of a protest."

Human Rights Watch called for an independent investigation into the killing of the nine Brotherhood members, stressing that the ongoing investigation under the Supreme State Security Prosecution is insufficient. 

"Independent prosecutors under the Prosecutor General should investigate the killings, not prosecutors from the agency that authorised the fatal raid," the group said in its report.

Egypt's acting prosecutor general referred 198 alleged Muslim Brotherhood members to military judiciary in July, for complicity in "terrorist crimes" in Giza and Gharbia.

The prosecution said its investigation revealed that the Brotherhood formed a committee to serve as the group's military wing, under the supervision of late Brotherhood leader Abdel Fattah Ibrahim.

Ibrahim was among the Brotherhood leaders killed in the raid.

Egypt listed the Brotherhood as a terrorist organisation in December 2013 and insists it is behind the wave of militancy which has targeted security personnel since July 2013.

The Brotherhood continuously denies the accusations.