DHAKA (AFP) - Bangladesh police have arrested more than 3,000 people in a sweeping nationwide crackdown following a spate of gruesome murders, they said Saturday (June 11), as the prime minister vowed to catch "each and every killer".

Those detained include 37 suspected Islamist militants and hundreds of potential criminals who previously had warrants out against them, as well as several hundred ordinary arrests, police said.

Bangladesh is reeling from a wave of brutal killings that have spiked in recent weeks, with religious minorities, secular thinkers and liberal activists the chief targets.

"We have arrested 3,155 people including 37 Islamist militants as part of the special drive over the last 24 hours," A.K.M Shahidur Rahman, deputy police inspector general told AFP.

"The militants included 27 members of Jamayetul Mujahideen Bangladesh (JMB)," he said.

The JMB is one of the main domestic militant outfits blamed by the government, which rejects claims from Islamic State group and a South Asian branch of Al-Qaeda that they are behind the killings.

The country's Prime Minister Sheikh Hasina told a meeting of her ruling Awami League party Saturday that police would stamp out the violence.

"It may take time, but God willing, we will be able to bring them under control," Hasina told a meeting of her ruling Awami League party on Saturday (June 11).

"Where will the criminals hide? Each and every killer will be brought to book as we did after the 2015 mayhem," she said, referring to a deadly transport blockade last year organised by opposition parties.

However, Bangladesh opposition parties immediately accused the police of using the crackdown to suppress political dissent.

"Hundreds of opposition activists have been arrested in the police drive," Bangladesh Nationalist Party (BNP) secretary general Fakhrul Islam Alamgir told AFP.

"In the name of the crackdown against Islamist militants, many ordinary and innocent people are being detained." Hasina has accused the BNP and the country's largest Islamist party, Jamaat-e-Islami, of orchestrating the attacks after they failed to topple the government in last year's transport blockade.

Police detained some 350 people in the country's second-largest city of Chittagong and its surrounding areas.

They include one suspect in the murder of Mahmuda Begum, the wife of a top anti-terror police officer who was fatally stabbed and shot last weekend.

Her husband had led several high-profile operations against the JMB in Chittagong and her killing prompted the police to vow to catch her killers.

"We suspect Shahjahan Robin as the prime offender in the murder of (anti-terror officer) Babul Akter's wife," Chittagong police chief Iqbal Bahar told AFP.

In recent days an elderly Hindu priest was found nearly decapitated in a rice field, while a Christian grocer was hacked to death near a church, with Islamic State group claiming responsibility for the killings.

A Hindu monastery worker was found hacked to death Friday (June 10) in the northwestern district of Pabna.

Police have targeted domestic militant outfits, however, specifically the JMB, with five members of the group shot dead in gunbattles this week.

Nine members of the JMB were arrested in Rajshahi, Shariful Islam, a police inspector in the northwestern district said Saturday (June 11).

Several attacks have occurred in the district including the killing of a liberal professor in April.

As well as the arrests, police said they had seized nearly 1,000 motorcycles across the country.

Motorbikes have been used in many of the attacks, with the government recently announcing a ban on motorcyclists carrying more than one passenger.