Gaza, Alray - A human rights group said Saturday that it was "deeply disturbed" by reports that an armed Israeli man dressed in a police uniform sexually assaulted two Palestinian boys in the Jordan Valley in April.

Defense for Children International Palestine said that in late April an Israeli man driving a white car with yellow Israeli plates approached two 14-year-old boys attending goats north of Jericho, and with his firearm visible, ordered them to strip before sexually assaulting them one at a time.

The grandfather of one of the boys said that the Palestinian Authority Liaison office submitted a complaint to Israeli police, but the attacker has still not been found.

"It's been three weeks since these kids were sexually assaulted, and they live in fear with their attacker still on the loose," Ayed Abu Eqtaish, Accountability Program director at DCI-Palestine, said.

"We urge Israeli authorities to carry out a swift investigation and apprehend the suspect before he attacks again."

Israeli investigators have reportedly obtained statements from the boys, who said they would be able to identify their attacker in a lineup.

They described the man as average height, black hair, in his 30s and with a mole on his left cheek.

According to their testimony, the boys saw their attacker in the same area a few days after the assault and hid until he drove away.

Since 2009, there have been at least 20 cases of children alleging sexual abuse and threats by Israeli forces while being interrogated, DCI-Palestine says.

This is the first case to be documented where sexual abuse has taken place by an Israeli perpetrator in uniform outside of arrest or interrogation, the group added.