NEW YORK — A lawyer for one of three South American soccer officials charged in the FIFA bribery scandal labeled a key witness at their U.S. trial a “serial liar” on Friday over accusations that his client used hand gestures in court to threaten the witness.

Prosecutors have asked the judge to revoke bail for Manuel Burga and jail him, saying he twice stared at the witness as he testified this week and ran his fingers across his throat in a slicing motion.

In arguments made Friday with the jury gone for the day, defense attorney Bruce Udolf objected to letting the witness, Argentine former sports marketing executive Alejandro Burzaco, tell the judge what he saw from the witness stand.

“From my point of view, Mr. Burzaco is a serial liar who will say anything,” Udolf said.

U.S. District Judge Pamela Chen said she would hold another hearing next week to have Burzaco testify about the allegations of witness tampering. She also agreed that Burga, who’s under house arrest, should be examined by a dermatologist to try to back up his claim that he was merely scratching a rash on his neck.

The bizarre episode came amid nearly four days of testimony by Burzaco describing how he brokered tens of millions of dollars in bribes paid to soccer officials in exchange for their influence in awarding lucrative broadcasting and hosting rights for the World Cup and other major soccer tournaments.

On trial are Burga, the former president of Peru’s soccer federation; Jose Maria Marin, the former president of Brazil’s soccer federation; and Juan Angel Napout, ex-head of Paraguay’s soccer federation. All have pleaded not guilty to racketeering conspiracy and other charges in the sprawling investigation of FIFA, soccer’s governing body.

Burzaco, who is cooperating with U.S. authorities as part of a plea deal, testified that his firm gave bribes totaling $4.5 million to Napout, $3.6 million to Burga and $2.7 million to Marin. He also claimed he has been the subject of death threats in Argentina because of his cooperation against powerful soccer officials.

More cooperators are expected to testify for the government in federal court in Brooklyn in the coming weeks. The list could include Jose Hawilla, a sports marketing executive from Brazil who became an informant in the investigation.

Burzaco testified about a meeting at a cafe in Buenos Aires in 2014 with an associate who warned him about Hawilla.

The associate told him Hawilla “was cooperating with the U.S. prosecutors to try to grab other people and investigating corruption in soccer,” Burzaco testified.

Asked on cross-examination whether he was aware of any electronic surveillance, Burzaco responded that he had learned “that Hawilla was recording people.”