Jakarta – The parents of some 70 students who went missing after taking part in a major pro-independence rally in the troubled province of Aceh on Thursday went to the legislature for help, a rights activist said.

Director of the Iskandar Muda Legal Aid Foundation, Yacob Hamzah, said police arrested around 250 students taking part in the mass rally in Lhoskeumawe on Tuesday. They had been among the some 10,000 students who rallied outside the headquarters demanding the release of their friends who had been arrested during a similar rally the previous day.

"There are about 250 students still arrested at the police headquarters ... About 70 parents were seeking to know whether their children had been arrested or not," Hamzah told AFP by phone.

"They just want to have some certainty, if their children are arrested, then they want to see their arrest warrants and the children," he added.

The student protestors had rallied for three days since Sunday during which they flew the bright red Aceh separatist flag. The police first arrested 24 students Monday for raising the flag in a convoy around the city.

Tuesday's arrest came after security opened fire to disperse the protesters as they approached the local police headquarters. The shooting left three killed, a teenager highschool student, an eight-year-old boy and a policeman.

The police were also questioning 50 civilians who had been in the crowd during Tuesday's rally. The Kompas daily said that some of the questioned civilians were reportedly seen with bruises.

"If they turn out innocent and only happened to be trapped among the students during the bloody Tuesday afternoon rally, then they would be released immediately," North Aceh police chief Lieutenant Colonel Iskandar Hasan was quoted as saying.