The Benfica defender was the subject of interest from United in the January transfer window, with a £38m bid reportedly set to be made for the 22-year-old.
However, the upturn in form from Marcos Rojo and Phil Jones persuaded manager Jose Mourinho against making an offer and interest in the defender was subsequently shelved.
Speculation linking the Sweden international to United has since resurfaced in Portugal ahead of the summer window but Lindelof has insisted he remains focused on Benfica.
"I'm not saying anything about that [interest from United]. I say what I always say -- I have a contract with Benfica, and that's what I'm focused on.
"I just try to focus on what's important for me. I know a lot of things get written, but I don't think it's right for me to read it all the time. It wouldn't suit me to read rumours."
Mourinho spoke to reporters in Portugal on Monday but did not confirm whether he was interested in signing Lindelof.
“I will not say if I want him or not, I think it’s incorrect [to talk about him],” he said.
“Rui is not going to be happy with another club manager talking about a player who is his, and the president would not be happy to see that.
Manchester United summer transfer targets
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“Lindelof is theirs and as long as he’s theirs, he’s theirs.”
United are expected to bring in at least one centre-back, with Burnley’s Michael Keane touted as a potential summer signing.
Lindelof, meanwhile, said his future may become clearer after Sweden's World Cup qualifier against France in Stockholm on Friday.
He said: "My thoughts are with the national team. After that I'm going on holiday, so we'll see. But I have a contract, and that's where my thoughts lie. That's my answer."
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