Chinese police say they have rescued 89 abducted youngsters and arrested 369 people involved in human trafficking in an apparent effort to calm public disquiet at a rising tide of child kidnappings.

Beijing launched a widely publicised crackdown on child trafficking this year after an online campaign urged residents to photograph street children to help parents identify kidnapped youngsters.

The campaign demonstrated the outrage among citizens, who criticised the government for ignoring – or even hindering – the efforts of parents to find snatched children.

China’s public security ministry said on Wednesday that the latest arrests were made in connection with a six-month operation to break up a pair of “large criminal enterprises” involved in kidnapping children across 14 provinces.

“Two large criminal gangs involved in child trafficking have been successfully destroyed, once again showing the public security organs’ solemn commitment to the people,” it said, noting that abducted youngsters were sold for an average of about Rmb40,000 ($6,210) each.

State media said some of the rescued children had been taken in Vietnam by Vietnamese residents and sold in southern China.

In another case this month, police rescued eight babies, aged 10 days to seven months, who had been drugged with sleeping pills, state media said.

Many abductions involve infant or toddler girls being taken to serve as “child brides” – sold to families desperate for daughters-in-law in a culture short of marriage-aged women.

The infants are raised within the family, then forced to marry a “brother” when older.

Such trafficking has risen in recent years, demographers say – a sign of the high price the country is paying for its gender imbalance, exacerbated by its one-child policy.

Its families traditionally preferred boys. Although that preference is waning, China’s last census showed a surplus of 34m men.

The government estimates up to 20,000 children are taken every year.

“Child abductions have entered a phase of high frequency,” Chen Shiqu, head of the anti-trafficking office at the public security min­istry said in an interview posted on his blog this year.

Police say they have ­rescued 14,000 children since 2009. However, many families complain that off­icers sometimes refuse to register youngsters as ­missing.