Human Rights Watch (HRW) has urged Jordanian authorities to release five university students detained over allegations that they desecreted the Quran and engaged in "devil worship".

The Al al-Bayt university students, who were accused of ripping and burning Quran manuscripts while performing a "religious ritual" in a campus bathroom in the city of Mafraq, were assaulted by a crowd of other students before being detained two weeks ago.

HRW's statement, released on Tuesday, also called for the arrest of those who attacked the students.

"The students, who deny the accusations and have neither been charged nor taken before a judge, were assaulted by a crowd of other students, and their attackers should be brought to justice," said HRW.

The US-based rights group said that the sister of one of the detained students said that a group of about 200 other students attacked her sister and four male students on the university campus following the Quran desecration rumour.

"She said the attackers appeared to have targeted the five students because they frequently dress in black and are rock music devotees," the statement said.

Campus officials and student activists managed to pull the five students to safety, but local authorities then detained them and later handed them over to the security services.

All five deny any involvement in the alleged desecration.

The father of one of the male students told HRW that his son had phoned him in distress from the university campus on the morning of March 12 and begged for help, saying: "Father they are beating me and I don't know why."

The Jordanian news website al-Sabeel reported on March 21 that the Office of the Public Prosecutor had extended the students detention for another seven days while it investigated them for "sowing discord [fitna] and defaming religion".

The father of one of the five told HRW that, according to his lawyer, the authorities have not yet filed any charges.