A spokesman for Stansted Airport said passengers were being taken off the plane.
"They will be taken to a reception centre in the airport where police may wish to interview them about what they have seen. At some point police and the airline will arrange for their onward transportation to Manchester."
A Manchester Airport spokesman said:
"The plane - flight number PK709 - was travelling from Lahore and had 297 passengers on board. For further information for friends or family who were due to meet the flight at Manchester please call 0800 140 4007.
More top news
A nurse and writer from south London has written a poem to commemorate the Battle of the Somme.
'We are here' events in the capital captured in pictures by Londoners are trending on Twitter as the UK remembers the Battle of the Somme.
Detectives have released CCTV of man they want to speak to over the rape of a 20-year-old woman in Finchley.