FIFA investigator Michael Garcia has met Qatari officials as part of a corruption probe into the vote which gave the Gulf state the 2022 World Cup.
The meeting on Wednesday went ahead in Oman as UEFA president Michel Platini added his voice to calls for a new vote if corruption is proved.
US lawyer Garcia met a Qatari delegation in a Muscat hotel and the encounter was to continue Thursday, a source close to the talks told AFP.
The Qatari World Cup organising committee delegation had "four members, including a high-level official," the source said.
FIFA's executive voted in December 2010 to give Russia 2018 World Cup and Qatar the 2022 event.
Garcia is looking into whether there was corruption in the awarding of the tournaments. Focus on the meeting has increased since British newspaper The Sunday Times alleged that former Qatari football chief Mohamed bin Hammam paid more than $5 million to win support for Qatar's bid.
UEFA President and FIFA executive board member Michel Platini, who voted for Qatar, told L'Equipe newspaper that if the corruption allegations were proven there should be a re-vote.
"If there is proof of corruption, it will take a new vote and sanctions," Platini was quoted as saying.
Platini again rejected claims made by English newspaper the Daily Telegraph this week that he held "a secret meeting" with Hammam.
He did admit, though, that attending a lunch with then French president Nicolas Sarkozy and high-ranking Qataris had set him thinking about voting for the emirate.
The Sunday Times said last weekend it had obtained millions of emails, documents and bank transfers relating to alleged payments by Hammam when he was a FIFA vice president.
British media reports in March said some FIFA executive board members were unwilling to be questioned by Garcia, who has said he will give his report to a FIFA ethics committee on June 9.
FIFA's annual Congress is to be held in Sao Paulo on June 9 and 10.
Platini is a potential rival to FIFA president Sepp Blatter in an election next year.
The 58-year-old former French footballing great insisted he had not been influenced by anyone to vote for Qatar.
"I was invited to a private lunch with the president of the Republic (France)," he said.
"On arriving at the lunch I found that the Qataris were there and I felt there was a subliminal message in them being present.
"However, I would emphasise that I went to the lunch to see the president and I did not know the Qataris would be there.
"Nobody told me who to vote for. Qatar never did and nor did Sarkozy," Platini said.