MUMBAI, India – A leading Christian human rights campaigner says “Indonesia’s pluralism in in grave peril” after the latest Islamist attack in the country.

On Wednesday, four militants with swords were shot dead by police in Riau province on the island of Sumatra. One police officer was killed after being hit by the van the militants were driving. A fifth assailant was captured.

The attack follows suicide bombings that killed 26 people – including 13 attackers – in Surabaya, on the island of Java. The attacks on Sunday targeted three churches in the city, including the Catholic parish church of Santa Maria.

Two families were responsible for the attacks, including one child who was only 7 years old.

The Islamic State group has claimed responsibility for all the attacks, including the latest in Riau.

“These further attacks compound the challenge and illustrate that this is a nationwide threat. Indonesia’s pluralism is in grave peril,” said Benedict Rogers, a human rights activist for Christian Solidarity Worldwide, specializing in East Asia.

Rogers told Crux the violence is “horrific,” and the most devastating since 2005, and highlighted the malevolence of the attackers.

“To bomb churches on a Sunday morning is outrageous, but for a family to carry out the attacks, using their own underage daughters and teenage sons, is the height of barbarity,” he said.

He also said the attacks are raising “grave concerns” about the dangers to Indonesia posed by radical Islamist ideology.

“The Indonesian government must urgently review its approach to deradicalization, particularly as they are confronted by over 600 people returning to Indonesia from fighting in Syria,” Rogers said, referring to those leaving the territory that was once controlled by the Islamic State group.

However, Rogers also said the more tolerant form of Islam once prevalent in Indonesia is also under threat.

“The Indonesian authorities must also realize the increasing threats to its proud tradition of religious pluralism and moderation posed by growing religious intolerance,” he said.

“Christians, Ahmadis, Shi’a and other minorities have been facing increasing restrictions and discrimination in recent years,” he said.

Over 87 percent of Indonesia’s 261 million people are Muslim, with 99 percent of those following Sunni Islam. Shias make up around 0.5 percent of the Muslim population, while Ahmadis are only 0.2 percent. Both Muslim minority groups are considered “unorthodox” by Sunnis, and the Ahmadis have even been declared “outside of Islam” by Sunni religious authorities.

Meanwhile, Christians are the largest non-Muslim religious minority, making up 10 percent of the population. There is also a small Hindu and Buddhist community in the country.

“The world must wake up to the fact that Indonesia’s pluralism is in peril. Terrorist attacks such as the ones we have seen in recent days, and religious intolerance towards minorities, come from the same hate-filled cruel ideological source, which must be confronted and defeated,” Rogers told Crux.

He called on the Indonesian government to do several things to help protect the country’s religious minorities: Increasing protection at places of worship; ending the practice of forcibly closing places of worship; ending the culture of impunity for those who harass or threaten minorities; and reforming or repealing discriminatory laws – especially the blasphemy laws, the regulations on construction of places of worship, and the laws targeting the Ahmadi community.

“Indonesia has been rapidly losing its status as a pluralistic, moderate Islamic society over the past decade – we should no longer speak of Indonesia as a role model for pluralism, but rather as a society that is becoming increasingly intolerant, albeit with courageous moderate Muslims still trying to defend minorities and protect pluralism,” Rogers said.

The human rights expert also said the defeats suffered by the Islamic State group in Syria and Iraq pose special dangers, as former fighters return to their homes in Southeast Asia.

“There is a real danger that Islamic State views Southeast Asia – particularly Indonesia, Malaysia, the Philippines, southern Thailand – as a recruiting ground and as a place to establish a new base. ‘Returnee’ jihadis from Syria form a key part of this,” he said.

Indonesian President Joko “Jokowi” Widodo has promised that the country’s security forces would root out and destroy Islamist militant networks.

“I ask all people to join together in the fight against terrorism and radicalism,” the president said. “It’s against our religious values, the precious values of God and diversity.”

Meanwhile, in Surabaya, the parishioners at Santa Maria Church are still “haunted by the trauma,” according to Fransiskus Xaverius Ping Tedja, the security coordinator at the parish where six people died.

“There has been an increase in the number of people attending Mass, because they want to pray together for the victims,” he told ucanews.com.