An Indian Islamic preacher, Dr Zakir Naik, whose teachings were popular with one of the terrorists in the Dhaka cafe attack, has denied advocating terrorism as the authorities in India and Bangladesh investigate whether his sermons could radicalise South Asians.
Bangladesh has banned Dr Naik's Peace Television - a 24-hour Islamic channel that broadcasts in English and Urdu, while India is poring over the contents of his sermons and the funding of his Mumbai-based Islamic Research Foundation.
At least one Indian government minister said his speeches "were a matter of concern".
The preacher has come under intense scrutiny since it was revealed that Rohan Imtiaz, one of the five gunmen behind the Dhaka cafe attack in which 20 hostages were killed, had quoted from Dr Naik's sermons on Facebook last year.
"I did not inspire any terrorist... I am a messenger of peace," Dr Naik said during a press conference last Friday via Skype from Saudi Arabia. He denied allegations that his speeches were inflammatory. "I have been branded a hatemonger without an iota of evidence."
Earlier in a YouTube response, he had said: "Every Muslim should be a terrorist to anti-social elements like rapists and murderers."
Dr Naik, who was born and raised in Mumbai, founded the Islamic Research Foundation in the early 1990s. He claims to have more than 100 million followers and his lectures are reportedly seen in more than 125 countries.
Last year, he launched Peace Television in China and was awarded the King Faisal International Prize in March last year for "service to Islam" awarded by Saudi Arabia.
But he has also faced controversy. In 2010, he was banned from entering Britain for making inflammatory remarks that "seek to provoke others to terrorist acts".
Asked whether Dr Naik would be allowed to enter Singapore to preach, a Ministry of Home Affairs spokesman said it could not comment on specific cases.
But the MHA said the Government needed to "guard against foreign religious speakers, regardless of the faith they represent, who propagate divisive doctrines that advocate exclusivism, disrespect to other religions, or cause members of a particular faith to live apart from others in society".
Dr Naik's Peace Television, which is broadcast from Dubai and hosts Islamic scholars and preachers, was first denied permission to air in India in 2008. The government is asking cable operators to ensure they do not transmit the channel.
Dr Naik, who quotes from the Quran in his speeches, has appeared to support suicide bombers. But at the press conference last Friday, he said the footage of that particular speech had been doctored.
In other lectures, he has criticised the United States and described gay people as "patients suffering from a sinful mental problem".
His supporters say his teaching was being misrepresented and maintained he was the target of a witch-hunt, even as critics have accused him of belittling the Shi'ite and Ahmadi Muslim sects.
Without naming Dr Naik specifically, Indian Prime Minister Narendra Modi noted earlier this month that "preachers of hate and violence are threatening the fabric of our society".
Security experts said his sermons must be studied to see if they contained any inflammatory messages.
"His speeches are problematic. But it is a matter of judicial assessment whether it is incitement, advocacy or a provocation to other communities. There are legal standards,"' said Dr Ajai Sahni, the executive director of the Institute for Conflict Management.
Associates of Dr Naik said he would present himself for questioning by the Indian authorities if asked.
"When agencies summon him, he will come down. He spends six months out of India. He is ready to join any investigation," said Mr Mohsin Khan, one of Dr Naik's supporters and a volunteer at the All India Dawah Centres Association.