Sinn Fein has been accused by the deputy leader of the Democratic Unionist Party (DUP) of triggering a snap election in Northern Ireland to secure concessions from the UK Government.
Nigel Dodds said Sinn Fein forced the election, set to take place on March 2, because it is "seeking opportune political advantage".
Sinn Fein deputy first minister Martin McGuinness quit his post earlier this month citing irreconcilable differences with powersharing partner the DUP.
The deadline for Sinn Fein to renominate to the vacant post before an election had to be called passed on Monday evening.
His decision to quit was precipitated by the renewable heat incentive (RHI) scandal - a botched green energy scheme overseen by DUP ministers.
Mr Dodds told the Commons the DUP would not "bow down and give in to Sinn Fein's unreasonable demands".
He said: "What is this election about? It's very clear it is not about the RHI issue because had it been then we could have got on with sorting it out and indeed this election will serve to disrupt and delay sorting those issues out.
"What it's about is Sinn Fein seeking opportune political advantage, seeking to overturn the result of the election held just a few months ago and seeking to gain a list of concessions from the Government on legacy issues such as re-writing the past and putting more soldiers and policemen in the dock and other issues and more concessions and other concessions from the DUP.
"Let us be very clear. We will work through this election and afterwards to create devolved government that is stable in Northern Ireland.
"But let this House know and the people of Northern Ireland know that just as we have not given in to Sinn Fein demands in the past we will not bow down and give in to Sinn Fein's unreasonable demands going forward because that is what this election is all about."
Mr Dodds' comments came after Northern Ireland Secretary James Brokenshire delivered a statement in the Commons on the unfolding political crisis.
Responding to the concerns raised by Mr Dodds, Mr Brokenshire said: "I recognise that there are strongly held views on all sides and we do enter into an election period when I'm sure that these issues will be hotly and keenly contested.
"What I do very much welcome from what you have said is that willingness to engage, that willingness to work things through and that desire to get back into stable, shared, devolved government."