But he has criticised "some who have sought to score cheap political points".

Mr Robinson's comments come as Donaldson stepped down as DUP leader earlier today after he was charged with historical sexual offences.

But Donaldson has not resigned as MP for Lagan Valley, and Mr Robinson did not rule out a by-election in the constituency, saying: "What comes in the days and months in that regard are outside our control."

He added: "In the immediate aftermath of such shocking news, there will be some, and there have already been some, who have sought to score cheap political points, who have sought to engage in conspiracy theories, who somehow enjoy or will manipulate such devastating news for those involved.

"That's not our position. Our position is recognising that what has happened is difficult. We have taken the right and appropriate steps today as a party."

Mr Robinson also said the DUP was informed late last night about the allegations against Donaldson, and made the decision to appoint Mr Robinson as interim leader during a party meeting this morning.

The news that Donaldson had been charged with historical sexual offences shocked Northern Irish politics.

Michelle O'Neill, the Sinn Fein first minister of Northern Ireland, said: "My priority is to continue to provide the leadership the public expect and deserve, and to ensure the four-party executive coalition delivers for the whole of our community now and in the future."

Read more: Who is Sir Jeffrey Donaldson?

She added the case against Donaldson "is now a matter for the criminal justice system".

Jim Allister, leader of the Traditional Unionist Voice, said Donaldson's departure had "very wide ramifications for unionism".

"When the leader of unionism finds himself in this position, the damage is not limited to his party but impacts unionism as a whole.

"This needs to be a cathartic moment for unionism.

"Unionism must steady itself and cut adrift the Donaldson folly of accepting an Irish Sea border and rule by EU law."