Amid concerns that hardline voices are growing, the leader of the world's largest Muslim group, Indonesia's Nahdlatul Ulama (NU), is confident that the moderate way of Indonesian Islam will hold firm.

Not one of the NU's 60 million members is a terrorist, Dr Said Aqil Siradj said yesterday at a talk organised by the S. Rajaratnam School of International Studies.

"We are still huge. We have 22,000 pesantren (Islamic boarding schools), 240 universities affiliated to NU and 800,000 mosques throughout Indonesia. Nobody, not even one body, has ever been involved in terrorism," he said.

Speaking to The Straits Times in Bahasa Indonesia ahead of his talk, he acknowledged that social media had done much to erode NU's hold on followers and supporters.

"Things are different now for NU than they were 30 years ago. These days, there are more and more aspersions cast against NU," he said.

The 91-year-old organisation, formed in 1926 by a group of Muslim leaders to defend the traditional, tolerant nature of Indonesian Islamic practices against foreign influences, is finding itself having to counter the appeal of extremist preachers once more.

Its arsenal includes its NU Online website, "cyber armies" and more than 100,000 "NUtizens" - a play on the word netizens.

Dr Said Aqil said that he makes it a point to communicate constantly with NU's extensive grassroots network in villages throughout the sprawling archipelago.

However, observers have wondered if the messages get missed.

Last month, for example, he was reported to not have discouraged NU members from joining protests against Jakarta's gubernatorial candidate Basuki Tjahaja Purnama, who is Chinese, Christian and known popularly as Ahok, and is facing charges of blasphemy brought forward by hardliners.

Pressed to clarify his stance on Ahok, Dr Said Aqil told ST, citing Islamic scholarship: "The number one criterion for leadership is fairness. So, a fair non-Muslim leader is better than an unfair Muslim leader."

He added: "When I told Indonesians this, many were angry with me. They said I was defending him. But I was merely telling them what I had read in the literature. I have no political interest in Ahok."

As for the rising appeal of radical ideology which, he said, has caught on among a small minority in his country, Dr Said Aqil attributes this to three factors.

One is the shallow, literal reading of religious tracts. He said that once hardline views have sunk in, nothing, not even the threat of death, could change ideology-addled terrorists. "Death by hanging or shooting is what they want because they think it will get them into heaven," he noted.

The other two factors, he said, have economic roots: poverty and a lack of education. On this front, Dr Said Aqil took issue with what he saw as an ethnic imbalance in his country, saying: "In Indonesia, there are 50 conglomerates owned by the Chinese. Only eight belong to the Muslim 'pribumi'."

Many NU members who are poor "are very jealous of the rich Chinese and their conglomerates", he said. "But they will not become terrorists because I am able to manage them. They are loyal to NU's leadership."

He said one way NU's leaders try to keep their followers in check is to provide them with sufficient education, healthcare and financial support for their businesses, with support from the government.

Yet, he has also remained critical of the administration and President Joko Widodo, he added, albeit only in private. "He listens and he accepts such statements without anger. He is a good man," he said.

Stressing his commitment to moderation and religious pluralism, Dr Said Aqil said: "I always say our motherland must be peaceful before we talk about our faiths. Why? Because we build mosques, madrasahs and hospitals on land and if that land is not peaceful, what can we build these on? Air?"