Indonesian police escort the seven teenage suspects into the courthouse in Curup, Bengkulu province, on May 10, 2016

Seven Indonesian teenagers were jailed Tuesday for the brutal murder and gang rape of a 14-year-old girl that sparked a national debate on sexual violence.

They were among a gang who set upon the schoolgirl while she was on her way home in a small village on the western island of Sumatra.

Her battered body was found three days later in woods, tied up and naked, and 12 people were arrested over the attack.

On Tuesday seven attackers, aged 16 and 17, were found guilty at a court in the Curup district of Sumatra and sentenced to 10 years in jail each.

"This is in line with our demands," said Eko Hening Wardhono, an official from the attorney-general's office, adding that police were still investigating the other five.

A further two suspects are still on the run.

The crime took place in early April but it only caught the attention of the nation a month later, as reports of the incident went viral on social media and tens of thousands signed online petitions.

The case led activists to call for harsher punishments for sex attackers and sparked protests in the capital Jakarta. It also prompted President Joko Widodo to call for better protection for women.

It has drawn comparisons with the fatal gang-rape of a student on a bus in Delhi in 2012, which sparked mass protests and led to an overhaul of India's rape laws.

Activist Rita Pranawati, from government-backed rights group the Indonesian Child Protection Commission, welcomed Tuesday's jail terms but said more needed to be done to tackle the root causes of sexual violence.

"Cases like this happen due to various reasons, from parenting problems, to bad education and drinking problems," she said.

Sexual violence against women is rampant in Indonesia, according to the National Commission on Violence Against Women.