VILNIUS - Five passengers on board a Ryanair flight that was intercepted by a Belarusian warplane and forced to land in Minsk on Sunday did not reach their final destination, the Lithuanian chief of criminal police said on Monday.

Belarus's action, which resulted in the detention of dissident journalist Roman Protasevich who had been on board, drew international condemnation. The plane had been flying from Greece to Lithuania.

The Lithuanian police criminal chief Rolandas Kiskis said he would not comment on the identities of the people who remained in Minsk.

Ryanair boss Michael O'Leary, who referred to the incident as a state-sponsored hijacking, said earlier on Monday he believed security agents had been on the flight and had also disembarked in Minsk.

That would mean the operation had effectively been coordinated with spies operating on the ground in Greece.

A Belarusian university in Vilnius said one of its students, Sofia Sapega, 23, who had been travelling with Protasevich, had also been detained when their flight was diverted there from Vilnius. The university demanded her release.

Lithuanian police are questioning the passengers who later disembarked in Vilnius after the flight finally reached its destination, and are examining the aircraft, Kiskis said.

The investigation could take months, Lithuania's deputy general prosecutor said.

(Reporting by Andrius Sytas, writing by Alan Charlish and Justyna Pawlak; Editing by Alison Williams and Gareth Jones) ((alan.charlish@thomsonreuters.com; +48 22 104 25 27 ;))