It had been rumoured earlier in the week that the two clubs had agreed a deal for the Belgium centre-back to move to Old Trafford.
However, Vermaelen, who is currently on international duty at the World Cup in Brazil, has dismissed the speculation saying that his future is as yet undecided.
“I know there has been a lot of talk and a lot of rumours but the only thing I can say is that it’s not true,” he told Sky Sports.
“Everybody understands my situation at Arsenal and that I have one year left.
“I understand that people are going to talk but I am here in Brazil and I am enjoying my time and I’m focused on what I am doing.”
When asked if he had discussed his role at Arsenal with manager Arsene Wenger, the 28-year-old refused to be drawn on the matter.
“We talk a lot when I am at Arsenal but it’s not what I am going to discuss here, it is something you are going to have to ask him,” he added.