Iran faces possible punishment after one of its competitors pulled out of a world championships heat involving an Israeli, swimming's world body has warned.
Executive director Cornel Marculescu said FINA had written to Iranian authorities seeking an explanation of Mohammad Alirezaei's decision not to contest the men's 100m breaststroke heat in Shanghai.
"We are checking. I'm looking for the Iranian," Marculescu told AFP in an interview on Friday, adding that he became concerned when he saw a statement from Iranian sports authorities.
"There was a declaration... that the policy is to boycott all events where Israel is swimming," he said. "We cannot accept this because our constitution says no discrimination by politics, by religion, by sex, nothing."
"Politics can be somewhere else. The pool is a place to do something else, but no politics. I've sent them a letter. We want to understand what happened," Marculescu added.
Alirezaei and Israel's Gal Nevo were both listed for heat four of the 100m breaststroke last Sunday. Nevo timed 1min 2.32sec, the 45th fastest in qualifying, but Alirezaei did not start the race.
Marculescu said any allegations of wrongdoing could be brought before FINA's disciplinary panel. The World Jewish Congress has already called for Iran's suspension from international sports events following the incident.
"We have to look carefully at what (happened) but we don't accept discrimination. It's in our constitution," Marculescu said.
"We have a disciplinary panel. The rules are there, the sanctions are there. If something is wrong we'll apply the procedure like anything else... when we have all the information we will do whatever is necessary," he added.
At the 2008 Beijing Olympics, Alirezaei also missed a 100m breaststroke heat involving an Israeli but said he was feeling unwell, an explanation that was accepted by the International Olympic Committee.
Suspicions were raised again last year when an Iranian wrestler pulled out of a world championships bout against an Israeli in Moscow. The Iranian team said the withdrawal was for medical reasons.
At the 2004 Athens Olympics, Iran's double world judo champion Arash Miresmaeili refused to compete against Israel's Ehud Vaks for political reasons.
Sport was again a flashpoint in February, when Iran demanded London 2012 Olympics organisers withdraw their logo for the Games, claiming it spelled the word, "Zion".