US child welfare officers are investigating allegations that the Cuban boy at the centre of a bitter custody battle was abused by his grandmothers during their high profile meeting last week.

Six-year-old Elian Gonzales has been staying with relatives in Florida since he was shipwrecked while illegally tring to enter the United States.

His mother and stepfather were among those who died in the attempt. The boy's natural father is fighting for him to be returned to Cuba and has made a fresh appeal to the US authorities.

The latest move in a much publicised and highly politicised wrangle follows an interview on Cuban state TV in which one of the grandmothers said that she unzipped the boy's flies and later bit his tongue as a way of making him relax during a meeting in Miami nine days ago.

The two grandmothers returned to Cuba this week after an unsuccessful attempt to take Elian away from the Miami relatives, who have been caring for him since he was rescued from the Atlantic Ocean more than two months ago.

The extraordinarily frank interview on Cuban television by Elian's paternal grandmother, Mariela Quintana, led to an anonymous phone call to the Florida Department of Children and Families.

Surrounded

All allegations of child abuse have to be investigated within 24 hours, and two welfare officers have been to Elian's temporary home in Miami to try to discover what happened.

The meeting took place in the Miami home of the Dominican nun and university president, Sister Jeanne O'Loughlin, and was ordered by the immigration service in an attempt to break the deadlock between the Florida and Cuban branches of the Gonzalez family.

Sister Jeanne's house was surrounded by television cameras, police and anti-Castro demonstrators.

Mrs Quintana told Cuban television that Elian was very nervous when he saw his grandmothers, their first meeting in more than two months.

Cultural misunderstanding

She asked him if he had lost his tongue. She put her finger in his mouth, pulled his tongue and bit it.

Then, laughing, she told the interviewer that she unzipped the boy's flies and asked to see his private parts to determine whether they had grown in the two months that he had been away.

People sympathetic to the two women say there has been a cultural misunderstanding and argue that such banter between a grandmother and child is not unusual in Latin families.

But that is not how it is being viewed in Miami. A spokesman for the Miami relatives who have been caring for Elian denied that they tipped off the authorities.

This latest development could work to their advantage, as they fight to keep the boy in the United States.

Repatriation

If child welfare experts believe the boy is at risk from his grandmothers, their testimony could be powerful ammunition at a federal court hearing to determine whether Elian should be returned to Cuba.

The case is due to start in just over two weeks' time.

The natural father of Elian - Juan Miguel Gonzalez - has urged Washington to protect his son from political harassment and media intrusion while the boy remains in the US.

Mr Gonzalez has also asked that Elian be removed from the care of a great-uncle, Lazaro Gonzalez, and placed with another US relative who supports the boy's repatriation to Cuba.

The requests were made in a letter sent to US Attorney General Janet Reno and Doris Meissner, commissioner of the Immigration and Naturalisation Service (INS).

Mr Gonzalez, who has backed Havana's efforts to seek Elian's repatriation, called on the US Government to respect the ruling of its own immigration officials and return the boy.

In a reference to the ruling by the INS last month, he said: "Let my son be given to me in line with the January 5 decision."

The father's letter was made public in Havana by President Fidel Castro's government, which has thrown its official weight behind Juan Miguel Gonzalez in the protracted dispute.

The situation has posed a tricky problem for Washington, which does not have formal diplomatic ties with Havana.