Having survived relegation from the Championship last season, Harris is eager to bring in reinforcements and there are reports claiming he is looking at a new goalkeeper, having lost three shot-stoppers this summer.
David Martin was snapped up by West Ham United, Ben Amos' loan from Bolton Wanderers came to an end, while Jordan Archer has opted to move when his contract expires at the end of this month.
Ipswich Town star Bartosz Bialkowski has been linked with a switch to The Den but Harris has refused to delve into specifics regarding his transfer plans.
"We've been linked with players. Some are right and some come completely from nowhere, players from countries where we've never heard of the player," he told London News Online. "We have never recruited from abroad, so it's not likely we will sign one from Outer Mongolia on a 12-year contract.
"Some will be true – that we have enquired about or made a bid for. Sometimes reports come out but we like to do our business in private and not alert other clubs to what we're doing and what we're spending.
"When it does come out it comes out from one place – and that's an agent. I won't be talking about individual players at other clubs."