The American father at the center of an international child custody battle is waiting to learn whether his 9-year-old son will return with him to the U.S. in time for Christmas.

Brazil Chief Justice Gilmar Mendes could rule Tuesday on the fate of Sean Goldman. David Goldman, the boy's father, and Brazil's attorney general are trying to enforce a lower court order that said the boy should be handed over to his father — despite attempts by a Brazilian stepfather to retain custody. Goldman would like to have his son back with him before Christmas.

In 2004, Goldman's wife, Bruna Bianchi, took his son Sean to her native Brazil.

Goldman says it was to be a two-week vacation, but she stayed and so did the boy. She eventually obtained a Brazilian divorce from Goldman and remarried.

Goldman was already seeking his son's return under an international treaty that covers cross-border child abductions when his former wife died last year giving birth to a daughter.

President Obama, the U.S. Congress and Secretary of State Hillary Clinton have all urged the child's return, and a U.S. congressman traveled to Rio on Thursday to continue lobbying for Sean's return.

On Thursday, another Supreme Court judge blocked a decision by a federal court earlier in the week ordering the boy be returned to U.S. authorities within 48 hours.

Goldman, who lives in New Jersey, flew to Brazil Thursday after the federal court ruling.

At the airport, an unidentified Brazilian woman in the crowd screamed at Goldman as he was leaving: "Leave your son here because he is happy! Don't take him away. You will regret it later; he doesn't know anyone in New Jersey."

Goldman showed no reaction to the woman's shout and was led by military police to a black SUV.

U.S. Rep. Chris Smith, who has been supportive of Goldman's fight and raised it in Congress, said upon landing in Rio that this case fell under international law and that the boy had been illegally taken away from Goldman.

"Child abduction is a serious crime and now for over five years David has been trying to get his son," Smith said. "We hope this is the end game and that he'll be reunited with his only father, and that's David Goldman."

But Goldman's own attorney had warned that additional appeals could block the transfer of his son.

"The hand-over can be halted," said Ricardo Zamariola, Goldman's attorney, referring to a possible Supreme Court appeal by the family that now has custody of the boy.

Previous rulings favorable to Goldman have been scuttled by Brazilian courts. Zamariola said he was certain lawyers for Joao Paulo Lins e Silva, the Brazilian stepfather with whom Sean lives, would appeal Wednesday's federal court ruling to surrender the boy. Zamariola said he did not expect a final resolution until at least the first half of 2010.

The stepfather's attorney, Sergio Tostes, has declined to comment.

The boy's maternal grandmother says Sean wants to stay in Rio and has filed a separate petition with the Supreme Court asking that the boy's desires be considered. A similar request from the Brazilian family was denied earlier this year.

The child, who has dual citizenship, has been shielded from speaking directly to the news media.

Goldman and Sean were reunited in February for the first time since his son was taken to Brazil. They have not seen each other since June.

The Associated Press contributed to this report.