Police in the Indian state of Assam in the east of the country have launched a crackdown on underage marriage, and arrested more than 1,800 men on Friday.

The state's chief minister, Himanta Biswa Sarma, said a statewide operation was underway "against those violating provisions of Prohition of Child Marriage Act," and confirmed the number of arrests in a Twitter post.

The minister went on to say he had asked police to adopt a "zero tolerance" approach against what he called an "unpardonable and heinous crime against women."

India has highest amount of child brides — UN

Police began making arrests on Thursday night, with those taken into custody including people who helped register underage marriages in temples and mosques, Sarma told Reuters news agency.

"From Muslims to Hindus, Christians, tribal people to those belonging to the tea garden communities, there are men from all faiths and communities who got arrested for this heinous social crime," Sarma told Reuters news agency.

"Child marriage is the primary reason behind child pregnancy, which in turn is responsible for high maternal and infant mortality rates," he said.

According to Indian law, it is illegal for girls under the age of 18 to marry, but the law is often flouted.

The UN estimates India has the largest proportion of child brides in the world at around 223 million, a third of the global total.

Around 1.5 million underage girls are married each year UNICEF said in a report from 2020.

Reuters material contributed to this report.

kb/sms (Reuters, DW sources)