Police in Assam have arrested more than 1,800 men for marrying or arranging marriages to underage girls, launching what the eastern Indian state’s chief minister said on Friday was the start of a sustained crackdown on the practice.

Police began the arrests on Thursday night, and more were likely, including of people helping to register such marriages in temples and mosques, Himanta Biswa Sarma told Reuters.

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

Marriage under 18 is illegal in India, but the law is openly flouted.

The United Nations estimates that the country is home to the largest number of child brides in the world at around 223 million. Nearly 1.5 million underage girls get married there every year, UN children’s agency Unicef said in a 2020 report.

“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 said.

The Assam government has registered cases related to child marriage against 4,004 people, he added.