Iranian authorities have vowed revenge after a suicide attack killed 27 border guards belonging to the Islamic Revolutionary Guard Corps (IRGC) on its southeastern border.

Iran’s Supreme Leader Ayatollah Ali Khamenei issued a statement saying, “A group who devoted themselves to protecting our borders and guard our security were martyred in an attack by terrorists.” The statement continued, “The connection between the agents of this crime with the spy agencies of some countries in the region and outside of the region is certain. The responsible agencies of [our] country must focus on that and pursue it seriously.”

The al-Qaeda-linked-Salafist extremist group Jaish al-Adl took credit for the attack in the southeastern Sistan and Baluchistan province. Iran has long complained that Pakistan has not taken seriously the threat this group poses to Iran and has not done enough to deter their attacks.

Commander of the IRGC Mohammad Ali Jafari issued a statement requesting that Pakistan take a more aggressive approach to this group on their border. “From the brotherly government of Pakistan and the security institutions and the army of this neighboring country, it is expected — with increasing actions and security measures on the shared borders with the Islamic Republic of Iran, the arena for takfiri terrorists and the mercenaries of the enemies of both countries — to remove the potential from any anti-security and hazardous action from them by confronting them firmly,” read the statement from the IRGC commander.