It added that "officers based at Heathrow are now investigating", along with colleagues from the airport.
A Heathrow spokeswoman said the airport was working with police to "prevent any threat to operational safety".
A spokesperson from the airport confirmed that a drone was sighted near or within the airport, prompting the precautionary suspension of departure flights.
ITV reporter Sarah Rodgers was among those now grounded at Heathrow. "We apologise to passengers for any inconvenience".
Another said: "So, waiting to taxi on flight to DC, they've just shut the engines off due to a reported drone at Heathrow".
Hackers leak data stolen from German politicians and celebrities
No politically sensitive document seem to have been published, RBB reporter Michael Götschenberg, who researched the hack, said . Fietz said a preliminary investigation indicated that "no sensitive information or data" from Merkel's office had been leaked.
Several passengers stuck at the airport - including those on board aircraft - have also tweeted to confirm that they have been told about the drone sighting. "Like WTAF?!", one wrote.
Mr Grayling said: "We are in contact with Heathrow Airport concerning the drone sighting. Apparently we can't take off due to #drone sighting!"
York said he is "absolutely certain that there was a drone flying throughout the period that the airport was closed".
"The control tower has no idea when will be allowed to depart. - at Heathrow Airport".
It comes after drone sightings resulted in around 1,000 flights being cancelled or diverted at London's Gatwick Airport over three days before Christmas.
Student Gabriella Linning, 20, said she is on a grounded flight to Newcastle, told MailOnline the pilot of her plane said passengers should let staff know if they wish to disembark. This is to be combined with the ability to issue up to £100 fixed penalty notices on the spot to anyone seen operating a flying toy in a rogue-like fashion, and an extension of exclusion zones around runway ends at airports.