Theresa Villiers rules out suspension of Northern Ireland Assembly

Theresa Villiers has told MPs that despite a request from the DUP, the government does not think the time is right to suspend Northern Ireland's devolved institutions.

However, speaking in the Commons, the secretary of state said that if circumstances changed, the government would review its options.

A fresh round of "intensive" cross-party talks will begin later.

The current crisis followed the murder of former IRA man Kevin McGuigan Snr.

He was shot dead in east Belfast on 12 August. The crisis was sparked by a police assessment that IRA members were involved in the murder.

In a statement to the House of Commons, Ms Villiers said there were two main sources of political instability - continued paramilitary activity and the failure to implement the Stormont House Agreement.

On Monday, the Democratic Unionist Party said there would be no meetings of the Stormont Executive unless the talks reached a satisfactory outcome.

Ms Villiers said that paramilitary organisations "should never have existed in the first place, they should not exist today and they should disband".

She said only parties fully committed to exclusively peaceful means should be allowed to participate in Northern Ireland's political institutions.

"I believe that all the parties in the Northern Ireland Executive are committed to those principles, but I am fully aware that the fallout from the murder of Kevin McGuigan and the continued existence of PIRA structures is a cause of grave concern," she said.

She said the Stormont House Agreement was the best way to build a better future of Northern Ireland, but that it must be implemented in full.

A row over welfare reform and the status of the IRA is threatening the stability of the power-sharing government at Stormont

Ms Villiers said without welfare reform being agreed, the budget passed by the executive in June "simply does not add up" and there was a real possibility the Northern Ireland Executive could start running out of money.

She added the government was prepared to legislate from Westminster on welfare reform, but only as "a last resort".

Arguing that suspending the institutions should be an option, the DUP's Nigel Dodds told the Commons: "Murder has happened, carried out by those who are linked to a party of government - just imagine if that were to happen here."

'Same problems'

The Belfast talks will take place at Stormont House.

Analysis: BBC News NI political editor Mark Devenport

The venue is where Ms Villiers and the Irish Foreign Minister Charlie Flanagan thought they had resolved the multiple problems facing the Northern Ireland power-sharing executive just before Christmas last year.

Instead, the two ministers will be back at the same place, tackling the same old problems, plus some pressing new ones.

The DUP insisted that, in the wake of Mr McGuigan's murder, Stormont could not go about its business as usual.

So, DUP leader Peter Robinson's announcement that his party will prevent executive ministers meeting around their round table in the coming weeks was predictable.

Whether the negotiations can resolve the continuing arguments over the current status of the IRA, welfare reform or the budget remains far from certain.

The Ulster Unionists withdrew from the executive after police said Provisional IRA members had a role in Mr McGuigan's killing and that the organisation still existed.

That was rejected by Sinn Féin - it said the IRA had "gone away".

But the Ulster Unionists said Sinn Féin's denial that the IRA existed caused a breakdown in trust and it left its government role.

The current talks are expected to last four to six weeks.