Swiss police said they were investigating an anonymous bomb threat at the FIFA congress in Zurich that led authorities to search the premises.
The threat was made by telephone to a Zurich-based newsroom on Friday morning, Zurich city police said, adding that no one had been evacuated from the congress.
However, participants in the world soccer congress, which paused for lunch 45 minutes earlier than expected, were initially denied re-entry into the auditorium while officers conducted a search, a Reuters witness said.
"A search was carried out. The premises have been cleared by the authorities," FIFA Secretary General Jerome Valcke told the congress after it resumed.
Congress participants and media representatives were let back into the auditorium following the search, with no additional security precautions.
Pressure is mounting on Fifa president Sepp Blatter to quit as politicians and sponsors lined up to demand action after the darkest day in its history which saw senior officials arrested on suspicion of "rampant" corruption.