GUATEMALA CITY (Reuters) - A Guatemalan judge has barred a son and brother of President Jimmy Morales from leaving the country pending an investigation into their role in a case centering on irregular payments, the attorney general's office said on Thursday.


Morales won election last year pledging to clean up Guatemalan politics after riding a wave of public anger over a corruption scandal that led to the arrest and trial of his predecessor as president, retired General Otto Perez.


But Samuel "Sammy" Morales, an older brother and a close adviser to the president, and Jose Manuel Morales, one of his four sons, have been questioned over suspicious payments linked to the mother of Jose Manuel's then-girlfriend in 2013.


The mother, who has not been identified, agreed to supply Christmas hampers to the national property registry, which is being investigated for suspected corruption, according to testimony given during a public hearing about the registry.


The woman sent the registry a 90,000 quetzal ($12,000) bill made out in the name of a local restaurant for 564 breakfasts, not Christmas hampers, according to the attorney general.


The breakfasts were not delivered, according to statements given by a witness during the public hearing.

It was not clear what happened to the Christmas hampers or why the woman submitted the bill through the restaurant.

Sammy Morales told local newspaper Prensa Libre on Wednesday he had helped obtain the bill from the restaurant as "a favor" to his nephew, but he denied it was part of a fraud scheme.

Neither Sammy nor Jose Manuel has been charged with any wrongdoing.

The president said he would not interfere in the matter but expressed support for his relatives.

"My wife and I fully support our son and believe that my brother is an honorable man," he said in a statement.

(Reporting by Sofia Menchu; Editing by Enrique Pretel and Peter Cooney)