Media playback is unsupported on your device Media caption The Irish tricolour was flown over Parliament Buildings for a time on Wednesday, as Gareth Gordon reports

Police have begun an investigation into how an Irish tricolour was flown over Stormont.

The flag appeared over Parliament Buildings for a time on Wednesday.

A spokesperson for the assembly said it was aware that "two flags were flown without permission from the roof" and it was investigating the incident.

DUP assembly member Peter Weir said he had been assured by the assembly that "these were rogue actions and are being fully investigated".

The roof and the fourth floor of Parliament Buildings are currently a construction site under the control of building contractors.

The assembly said that the flags were removed as soon as it was made aware of them.

Stunt

Mr Weir said he had written to the assembly speaker Mitchell McLaughlin and chief executive Trevor Reaney to demand an explanation.

TUV leader Jim Allister said it was "a serious breach of protocol and absolutely unacceptable".

"The incident demands an immediate and through investigation by the Assembly Commission, and given the provocative nature of the stunt there should also be a police investigation," he said.

The assembly spokesperson said the speaker would hold a briefing on Thursday for members of the Assembly Commission where the chief executive would "update them on any initial findings surrounding the incident".

"The Speaker is clear that the commission needs to be able to consider this matter in full possession of the facts of the situation," the spokesperson said.

"A full meeting of the commission will then be held on Monday when all commission members are available and when it is anticipated that more information will be known."

Sinn Féin MLA Gerry Kelly said the reaction by unionist politicians to the incident "can only be described as hysteria".

"This for some unionist politicians is a bigger crisis than anything that has happened over the past weeks," Mr Kelly said.