UEFA expressed surprise on Thursday at reports of a halftime incident in Chelsea's Champions League match in Barcelona and said it had received no complaint from the English side.
Chelsea manager Jose Mourinho refused to address a news conference after Wednesday's game, won 2-1 by Barcelona, and a team spokesman said they would make a report to European soccer's governing body about an incident in the players' tunnel.
"We are puzzled," said UEFA spokesman William Gaillard. "We have had no contact from Chelsea.
"The situation last night as far as we are concerned was rather normal.
"We had people in the dressing room area, probably more people than normal, and they didn't notice anything going on. We are rather surprised."
Media reports said Mourinho was upset that Barcelona manager Frank Rijkaard had talked to Swedish referee Anders Frisk at halftime and that a scuffle had occurred between team officials.
Gaillard said UEFA would talk to Chelsea about Mourinho's refusal to attend the mandatory post-match news conference and added he could face sanctions.