Gill rejected allegations that United were trying to intimidate French second division club Le Havre who say Pogba had agreed to join them before signing for the Premier League champions.
Le Havre have said they will take the matter to football's governing body FIFA.
"It's not intimidation but they can't insult us," Gill said.
"We are not intimidating Le Havre, we have no intention of intimidating Le Havre, they can take whatever action they fell appropriate," he said at a meeting of the European Clubs Association.
"We have done everything by the book, we are confident in that, they can take whatever action, we won't be insulted by Le Havre.
"It's an insult by Le Havre to suggest that Manchester United and employees of Manchester United have paid the parents and bought the player's parents a house.
"We will not accept the good name of Manchester United being trawled around Websites and the press saying we have done these things we are not allowed to do.
"If they want to take action, they can take action, we will defend our case in the football bodies, we are very comfortable about doing that."
Le Havre managing director Alain Belsoeur said last week that he had evidence proving United offered inducements for 16-year-old Pogba to join them.
Pogba is one of the most highly-rated young players in France and has captained the under-16 national team, but is yet to have his registration cleared to play for United.
The allegations first arose last month when Le Havre accused United of offering very large sums to Pogba's parents to end his contract with the French club.
Le Havre say United offered Pogba 3,500 pounds a week from when he turns 17 next March.
"Manchester United has today written to Le Havre to put it on notice that action will be taken if such allegations are repeated in relation to the transfer of Paul Pogba," United said in a statement.
Chelsea were banned last week by FIFA from registering any new players until 2011 for improper conduct when they signed Gael Kakuta from French club Lens in 2007.
