A U.S. man caught in a tug-of-war with his late ex-wife's relatives for custody of his son got a boost from Brazil's top prosecutor in a dispute that is testing an international child abduction treaty and heating up into a political tussle.

Attorney General Luis Inacio Adams filed an appeal with the Supreme Court late Friday challenging a decision by one of its justices suspending an order that David Goldman's son, Sean, be turned over to him.

Citing the Hague Convention on International Child Abduction, Adams warned in a briefing posted on the court's Web site that "failing to follow that accord will lead to the imposition of sanctions and damage the reputation of Brazil before the international community."

Goldman's attorneys also appealed.

For more than five years, Goldman has pressed his case in the United States and Brazil. Sean was taken by his mother in 2004 to her native Brazil, where she then divorced Goldman, remarried and ultimately died last year in childbirth.

The case gained momentum this week when an appellate court ruled the boy should be reunited with his father. Goldman flew from New Jersey to Rio de Janeiro — only to be put off yet again Thursday by the Supreme Court judge's decision, which blocked Sean's return pending consideration of the boy's testimony on his own wishes.

Goldman made an emotional plea Friday to be able to take his son home.

"I'm on my knees begging for my son to come home, begging for justice," Goldman said.

It was not clear when the Supreme Court will hear the new appeals; the justices went into recess Friday through Feb. 1, though they can hear urgent cases during that period.

Earlier, Sean's Brazilian relatives applauded Thursday's decision blocking his transfer, saying it was important that the boy's desires be taken into account.

"He has already lost his mother, and now he could lose his (half) sister, his closest link to his mother," Sean's maternal grandmother, Silvana Bianchi, told the Folha de S. Paulo newspaper.

But New Jersey Congressman Chris Smith, who is in Brazil supporting Goldman, questioned the merits of hearing testimony from a child who may be susceptible to pressure from adult relatives.

"If any court anywhere accepts information provided by a 9-year-old ... in front of a camera under duress, coercion or some other kind of manipulation, kidnappers around the world will rejoice," Smith said. "All they have to do is coerce their kidnapped victim to say, 'I want to stay in Japan, Brazil or anywhere."'

An independent attorney who specializes in the Hague Convention, which seeks to ensure that custody decisions are made by the courts in the country where the child originally lived, said it could set a bad precedent.

"If the Brazilian courts ultimately refuse to have the matter decided in New Jersey, it is an affront to international law and no child is safe to travel out of the United States," said Greg Lewen, of the Miami-based law firm Fowler White Burnett.

After the Thursday stay was issued, New Jersey Sen. Frank Lautenberg placed a hold on a bill renewing a trade deal that allows Brazil and other countries to export some products duty-free to the United States. Brazil received about $2.75 billion in benefits last year from the agreement, according to Smith.

The U.S. Embassy also issued a statement expressing disappointment at the latest delay in the case.

"The fact that the American Secretary of State made a statement regarding a decision made by the Brazilian Supreme Court indicates that we are on the verge of an institutional crisis between the two countries," said Sergio Tostes, attorney for Sean's stepfather.

Tostes then announced that the family was inviting Goldman to spend Christmas with them, though it was not immediately clear whether he would accept.

University of Brasilia political scientist David Fleischer said the case — along with Brazil's refusal to extradite Cesare Battisti, a fugitive ex-militant who is wanted in Italy for murder but remains in Brazil despite an extradition treaty between the two nations — is harming the South American country's reputation.

"This is a case involving an international agreement of repatriation of children that Brazil has signed," Fleischer said, referring to the Hague Convention. "So Brazil will a get nasty international image as a country that doesn't comply with the international agreements it has signed."