Northern Ireland's top police officer has said the force's "principle objective" is to police the decision to allow a parade down the Garvaghy Road in Portadown, but added this would not be done "at any cost".

Police Service of Northern Ireland (PSNI) Chief Constable Jon Boutcher said his overriding responsibility is to keep people safe.

He has also offered to meet both sides in the stalemate, the Orange Order and the Garvaghy Road Residents' Coalition.

There has been more than three days of stalemate over the Orange Order parade, which was due to happen on Sunday morning but has not due to protesters on the mainly nationalist Garvaghy Road.

Protesters remain along the road but the Orangemen who had been at Drumcree church since Sunday morning left overnight into Wednesday.

The Orange Order has said it is disappointed and frustrated by a "lack of a proper policing plan" to allow the march to go ahead.

Separate talks are continuing between Northern Ireland Secretary Sir Chris Bryant and the respective sides in an effort to break the stand-off.

The residents have also launched a fresh legal bid to stop the parade from going ahead, which is due to be heard on Friday.

Earlier, Boutcher said that the stalemate meant the police had "once again become the shock absorber of our society".

He also said that people needed to focus on "solving this situation once and for all".

Boutcher added that a "large scale criminal investigation" is under way into the unlawful blocking of Garvaghy Road, which prevented Sunday's parade.

"I have given a clear direction regarding prioritising the evidence gathering and a criminal justice process," he added.

Thousands of people, including the Sinn Féin First Minister of Northern Ireland Michelle O'Neill, blocked the road on Sunday and police stopped Orangemen leaving Drumcree Church.

Subsequent attempts since then have also been prevented by police.

On Monday, Assistant Chief Constable Ryan Henderson said police were not able to allow the parade because of an "unlawful and unnotified protest", adding that removing the protesters from the Garvaghy Road would have significantly jeopardised public safety.

Boutcher said his officers would "continue to police Drumcree and our communities independently and impartially".

"To be clear the upholding of the Parades Commission determination does not come at any cost," he added.

"The outstanding officers of the PSNI and our mutual aid colleagues will not allow society to implode into violent disorder and mob rule must not be allowed to win."

Unionist politicians have been highly critical of nationalist politicians from Sinn Féin and the SDLP who attended Sunday's protest.

The leader of the Democratic Unionist Party (DUP) Gavin Robinson said those in attendance had broken the law.

The DUP and Ulster Unionist Party will meet Boutcher later on Wednesday afternoon.

Ahead of the meeting, a DUP source said: "If people break the law they must be held accountable."

O'Neill has defended her involvement in the protest and said she was "standing up" for the community.

It appears, as things stand, that PSNI cannot police the Parades Commission determination.

It is hoping that an agreed way forward can somehow be found through talks and it continues to assess whether the determination can be enforced.

But any move would see hundreds of protesters back on the Garvaghy Road, in essence re-creating the circumstances that stopped Sunday's parade.

The PSNI also does not want to "torpedo" talks being held by the secretary of state.

Not for the first time, it finds itself in no-win situation, damned no matter which course of action it takes in the absence of some negotiated plan.

There is also unhappiness at how the Parades Commission presented the police advice in its determination.

The ruling said the police had "no information" the parade would result in disorder, only to look foolish 48 hours later.

However, a court judgement published on Tuesday night tells a different story.

It states a range of potential scenarios had been mapped out, from a peaceful parade to "violent disorder".

In just over a month's time, the PSNI will mark its 25th anniversary.

And here it finds itself – in the middle of a dispute which is older than it is.

The Drumcree parade, which in the 1990s sparked some of the most serious disorder in Northern Ireland's history, was due to go ahead for the first time in 30 years after a series of legal challenges.

Since 1998, the Order had been banned from completing its Drumcree march - and until this year had been repeatedly refused permission to finish the route by the Parades Commission, which was set up to adjudicate disputes.

The Orange Order is a Protestant pro-British organisation.

The Garvaghy Road had been part of the Drumcree route, but by the mid 1990s nationalist residents protested against the parade.

When the Orange Order was prevented by police from walking down the route in July 1995, there was a tense stand-off. It was the same for the next three years.

Violence related to the dispute resulted in riots, roadblocks and murders across Northern Ireland.