Chelsea coach Jose Mourinho declined to hold a press conference after his team's 2-1 Champions League defeat to FC Barcelona in protest over halftime contact between Barcelona coach Frank Rijkaard and referee Anders Frisk, reports AP.
Rijkaard acknowledged after Wednesday's game that he had spoken to Frisk during the interval but said Chelsea was exaggerating.
"I spoke to him, in a very polite way, for a few seconds about something which happened in the first half," Rijkaard said. "They're exaggerating all this. They are inventing something that didn't happen."
The Barcelona coach described Chelsea's behavior as "regrettable" and "incorrect" and denied rumors that the Swedish referee entered the Barcelona changing room at halftime.
Chelsea spokesman Simon Greenberg announced after the match that neither Mourinho nor the players would speak to the media until "an incident" had been resolved. Greenberg didn't give any details about the nature of the incident but said the club would make a complaint to UEFA.
Cited by sports newspaper Mundo Deportivo on Thursday, UEFA spokesman William Gaillard said that Chelsea hadn't yet filed a complaint while adding "it has said it will do so."
Coaches are obliged by UEFA to hold post-match press conferences after Champions League games and a failure to do so incurs a fine.
Spanish news agency Efe said the incident stemmed from Barcelona's assistant coach Henk ten Cate challenging Frisk in the tunnel to complain that he thought Chelsea's goal was offside.
Chelsea officials intervened to protest, Efe said, citing Barcelona officials. There were allegations that scuffles broke out.
Mourinho is known to object to conversations between match officials and coaches during games.
Last month, the Portuguese coach criticized a discussion between Manchester United coach Alex Ferguson with the referee at half time of the teams' goalless League Cup semifinal first leg at Stamford Bridge.
Wednesday's Champions League match was preceded by characteristically brash comments by Mourinho, with the coach noting that he had won as many Champions League titles one as Barcelona in all its history.
Mourinho served as an assistant with Barcelona from 1996-2000 before leaving to win the Champions League with FC Porto and then moving to Chelsea.
In his first full season with Porto, he led the team to the 2003 UEFA Cup and the Portuguese league and Cup double. A year later, Porto won the Champions League and retained the league title.
Barcelona won Wednesday's first knockout round, first leg on second-half goals by substitute Maxi Lopez and Samuel Eto'o after Chelsea took the lead in the 33rd minute courtesy of an own goal by Barcelona defender Juliano Belletti.
The return leg is at Chelsea's Stamford Bridge on March 8.