"It's a bit uncomfortable to give someone a rejection when no offer has come, but it looks like that's what I have to do," said Klopp on Thursday when asked about the role after Moyes was sacked on Tuesday morning.
Klopp has a contract with Dortmund until 2018 and said while United are "a really great" club, he was content with his lot, "because there are about 1,000 reasons to be super happy to work with this club."
Dortmund are second in the Bundesliga, made the quarter-finals of the Champions League and will face Bayern Munich in the German Cup final on May 17th in Berlin.
United are not the only club Klopp has been linked to.
Earlier this month he poured cold water on Spanish media reports linking him to Barcelona with their manager Gerardo Martino under pressure after his side failed to reach the Champions League semi-finals and lost in the Spanish Copa del Rey final to bitter rivals Real Madrid.
"No one has to give it any thought," Klopp told the BVB.de website in answer to the Barca rumours.