Sao Paulo sports director Adalberto Baptista has confirmed the Brazilian club recently turned down a 32million euros (£25million) offer for the attacking midfielder, currently representing Brazil at the Olympics, thought to have been tabled by United.
But the Sao Paulo chief has cooled rumours Premier League champions City could attempt to hijack the Red Devils' move for the 19-year-old.
He told Calciomercato.it: "Interest from Manchester City? We are not aware of it and we have not had contact with them."
Baptista also denied reports Inter Milan have made a 25million euros offer for the starlet, while adding that would not be enough to secure his signature, insisting it could take 70million euros to prise him away.
"An offer of 25million euros for Lucas from Inter Milan? We have not received written offers from Inter and that figure should not be enough, since we have already refused an official offer of 32million euros for our player," he said.
It is thought Sao Paulo are ready to offer Moura a new improved deal in a bid to keep him at the club and Baptista insists the youngster wants to stay.
He added to Band: "During the transfer window, there is a lot of speculation. Unfortunately until August 31, we'll have to deal with this.
"We know many European clubs want Lucas but we work with two facts. The first is that Sao Paulo don't think this is the moment to lose Lucas. We need him to win the titles our fans want.
"Secondly, Lucas himself does not think this is the moment to leave Brazil."
Asked if the club have set a price for the youngster, Baptista added: "We negotiate when the player effectively asks us to do so. Then we set a value below the buyout fee.
"Whenever a club comes to us (for Lucas), we ask them to pay the buyout fee that is 70million euros."
Meanwhile, Baptista dismissed reports Roma have made a bid for centre-back Rhodolfo.
He added: "They have not made any proposal for our player. The last official offer for him from Italy came from Juventus last year. Now there is nothing."
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