Police said Monday they have arrested two people in northern Vietnam for trying to transport a newborn baby to China as part of a baby-trafficking ring, the second suspected ring broken up in a week.

Police in the border town of Mong Cai in Quang Ninh province detained the two Vietnamese women early Saturday as they were about to cross the border into China with a 12-day-old baby boy, said Nguyen Thai Binh, the town's deputy police chief.

The two women, who were living illegally in China, told police they were hired by a Chinese woman to buy the baby for $875 from an unknown person in northern Thanh Hoa province, he said.

The women, aged 36 and 42, said they were paid $150, he said.

The women were transferred to provincial police for questioning. The boy was taken to a social welfare center.

Last week, police in Mong Cai arrested four men and two women suspected of trying to sell two newborn baby boys in China.

Last month, the U.S. Embassy in Hanoi issued a report describing widespread abuses in Vietnam's adoption system, including baby selling, corruption and fraud.

In response, Vietnam announced it would suspend the bilateral adoption agreement between the two countries as of July 1.

Vietnamese police have broken up dozens of trafficking rings in recent years that sold women and children to China or Cambodia.