BRASILIA (Reuters) - Brazil's presidential Chief of Staff Eliseu Padilha said Thursday's pre-emptive arrest of a group allegedly supporting the Islamic State (IS) showed the government is ready to act promptly to squash terrorist activity before the Olympics.

"This shows that Brazil is on its toes and monitoring any suspects that could become a threat," Padilha told foreign correspondents on Tuesday, adding that Brazilian security officials have been sent to France to learn about last week's truck massacre in Nice.

(Reporting by Anthony Boadle; Editing by Cynthia Osterman)