DHAKA: More than 3,000 people, including 37 militants, have been arrested across Bangladesh in a sweeping crackdown on Islamists to halt a wave of fatal attacks on minorities and secular writers, as Prime Minister Sheikh Hasina on Saturday vowed to catch "each and every killer".The militants arrested were operatives of the outlawed Jamaat-ul-Mujahideen Bangladesh (JMB), the outfit believed to have carried out most of the attacks on secular and liberal activists and minorities, including Hindus and Christians."Out of the 37 militants, 27 belong to JMB," deputy inspector general AKM Shahidur Rahman told reporters while reports said more than 3,000 suspects - mostly listed as thugs and criminals - were arrested over the past two days.Bangladesh launched the drive after a high-level meeting held by inspector general AKM Shahidul Hoque on Thursday. The anti-militant drive involved the paramilitary Border Guard Bangladesh and the elite anti-crime Rapid Action Battalion.Bangladesh has been witnessing a string of brutal attacks by Islamists. The ISIS and al-Qaida in the Indian Peninsula have claimed some of the attacks but government denies the presence of these groups in Bangladesh.Prime Minister Sheikh Hasina told a meeting of her ruling Awami League party that police would stamp out the violence."Where will they hide in Bangladesh," she said. "No one will get away. Bangladesh is a small country. It's not a tough task to find them. They will be brought to justice.""Each and every killer will be brought to book as we did after the 2015 mayhem (and) all their sources, financiers and patrons would be unearthed and brought to justice as well," she said, referring to the deadly transport blockade last year organized by opposition parties.She asked her countrymen to not be a bystander during such attacks as most of the attacks involved bike-borne assailants."Please don't play the role of an onlooker when you see that a person is under attack, rather, try to resist and catch the criminals ... police and (government) will stand by you," she said at the meeting at her official residence Gana Bhaban.But opposition Bangladesh Nationalist Party immediately accused the government of using the crackdown to suppress political dissent. It rejected the allegation that the party and its fundamentalist ally Jamaat-e-Islami were patronizing the attacks under an orchestrated plot against the government.BNP secretary general Fakhrul Islam Alamgir accused the government of arresting "hundreds of opposition activists in the name of crackdown against Islamist militants."The attacks since last year, which has left more than 30 people dead, has put Bangladesh under a global spotlight for failing to prevent such attacks.On Friday, a 60-year-old Hindu ashram worker was hacked to death by ISIS jihadists, days after another priest was killed by the same terrorist group in the Muslim-majority nation.In February, militants stabbed to death a Hindu priest at a temple and shot and wounded a devotee who went to his aid.In April, a liberal professor was brutally hacked to death in Rajshahi city. The same month, a Hindu tailor was hacked to death and Bangladesh's first gay magazine editor was murdered in his Dhaka flat by Islamists.