Police are hunting for drug traffickers who allegedly persuaded four minors to swallow and unknowingly attempt to transport more than 1,000 grams of heroin from Yunnan Province to Sichuan Province, the Legal Mirror reported Thursday.

Four girls of the Yi ethnic group from Butuo county, Sichuan Province, aged between 11 and 14, said that they were approached by a woman who promised to give them a total of 10,000 yuan ($1,627) to help her transport goods from Yunnan to Sichuan, according to police in Longling county, Yunnan Province.

The girls said that they were first taken to the city of Lijiang in Yunnan Province and then to another Yunnan city, Lincang.

The woman asked the girls to swallow the drugs on October 14 and led them to a van. The woman said she would wait for them at a bus station in Baoshan, Yunnan Province and together they would bring the drugs back to Sichuan.

"The four girls are minors. They did not know that the goods in their bodies were drugs. Nor did they understand that their actions were illegal," said a police officer, Zhao Hongbin.

Local police intercepted the van in Linglong county at 11:30 am the same day after receiving a tip-off.

The girls discharged 1.39 kilograms of heroin on October 15. They were then brought back to Sichuan by their families on Saturday.

The police are now trying to track down the woman and other possible accomplices.

Police warned that if citizens notice strangers suspiciously interacting with minors, they should call the police immediately.

Similar events occurred last month in Xi'an, Shaanxi Province. A 42-year-old woman surnamed Guo was detained by Lianhu district police, Xi'an on September 4 for swallowing and transporting more than 400 grams of heroin.

Guo said that she met a woman in Chengdu, Sichuan on September 3, who promised to give her 4,000 yuan to take drugs from Chengdu to Xi'an. 

Doctors removed two condoms filled with heroin from her body and Guo went on to discharge another 44 bags of heroin over the following two days, said police.