Amnesty International on Friday demanded the Hamas movement to condemn attacks on civilians after the group claimed a Jerusalem bus bombing that took place earlier this week.

The international rights group said in a statement that “deliberate attacks on civilians” could never be justified, calling on Hamas to reject rather than support such attacks.

Hamas on Wednesday claimed that a 19-year-old Palestinian from Bethlehem’s Aida refugee camp believed to be responsible for the attack was a “committed activist” for the group, applauding the teen after he allegedly detonated a bomb on an Israeli bus the day before.

The teen, identified as Abd al-Hamid Abu Srour, died from severe injuries hours after the bombing took place. Twenty others were injured in the blast.

While an Israeli gag order has prevented confirmation that Srour was indeed responsible for the attack, Israel’s police and security agency Shin Bet have confirmed that a Hamas member carried out the bombing, and a number of suspected Hamas activists have been detained from the Bethlehem area since.

Amnesty said that while it it was not initially clear that Hamas’ leadership or military wing had ordered the bombing, the potential involvement of the group in the attack was a “worrying development.”

– Read more: Amnesty demands Hamas to condemn Jerusalem bus bombing – MAAN