US parents have long turned to Guatemala to find children to adopt
The authorities in Guatemala have suspended the adoption of some 2,300 children by foreigners for at least a month to check for irregularities.
Officials said each case would be reviewed to see if the babies were genuinely being offered for adoption by their birth mothers.
In recent months, Guatemala has taken steps to improve its adoption system, plagued by fraud and corruption.
Last year, some 5,000 children were adopted, most of them by US parents.
In January, a new law took effect in Guatemala to comply with an international treaty on inter-country adoptions.
The legislation included having a central body to oversee adoptions, allowing only accredited adoption agencies and imposing a transparent fee system.
The government had been under pressure to curb a controversial trade where intermediaries could be paid thousands of dollars to arrange an adoption.
Guatemala's attorney general, Baudilio Portillo, said the cases being put on hold were already in the system before the new legislation took effect.
Mr Portillo said the cases would be checked "one by one" to see if the children being offered up for adoption were really the offspring of the parents whose names appeared on documents supplied by private lawyers.
If there were any doubts, DNA tests would be carried out.
The attorney general's move was prompted by concern expressed by Guatemalan legislators and the newly created National Adoption Council over possible anomalies and manipulation of DNA results in some cases.
Guatemala is second only to China as the source of babies adopted by US parents.
Last year, more than 4,700 Guatemalan children were adopted by Americans.
Last August, the US embassy began requiring a second DNA test to ensure that the baby presented at the start of the process, when the mother is also DNA-tested to ensure she is the child's biological parent, is the same child who receives a visa at the end.
US officials have said reports of babies being stolen from their mothers are unlikely to be true given these safeguards, but nevertheless it was sometimes difficult to ascertain the level of consent granted by the birth mother.
Last month, the Vietnamese government announced that it would stop accepting adoption applications from US citizens after 1 July, after a US embassy report in Hanoi cited cases in which children had allegedly been sold and families pressured to give up their babies.
Vietnam dismissed the claims as groundless and unfair.