Ronna Nirmala – The country's highest Islamic authority has slammed a hard-line group for attacking an Ahmadiyah mosque in Bandung on the eve of Idul Adha last week.

"We can't tolerate any attack even if it is in the name of justice," Ma'ruf Amin, chairman of the Indonesian Council of Ulema (MUI), said on Sunday in response to the attack last Thursday night by the Islamic Defenders Front (FPI).

He said that if mainstream Muslims had objections to the Ahmadiyah, whom the MUI insists is a heretical sect, they should not take the law into their own hands. "The authorities also must have the nerve to take action so that people don't have to do it themselves," Ma'ruf added.

Dozens of FPI members attacked the An Nasir Mosque in Bandung's Astana Anyar area last Thursday after seeing Ahmadis there preparing for the Islamic holiday of Idul Adha.

After their demands for the Ahmadis to stop what they were doing met with refusal, the hard-liners started destroying lamps and windows on the first floor of the mosque, with around 10 Ahmadis, including women, inside. The police did not take any action.

West Java Governor Ahmad Heryawan, who initially condoned the attack by claiming that the FPI had been provoked into violence, made an about-face on Sunday and said his office would send a warning letter to the group to demand that they stop using violence.

The governor said he would still give the group some leeway, but if they carried out their vigilante actions two more times, he would ban them.

"This is the first warning letter, and after the third, that's it. If they don't obey, we will erase them from the province's list [of approved organizations] and ban all their activities," Ahmad said.

Home Minister Gamawan Fauzi backed the call for taking action against the hard-line organization.