The British Government has said working relations at the Northern Ireland Executive have completely broken down.
Northern Ireland Secretary Theresa Villiers said she would not suspend the devolved institutions following the resignation of DUP ministers including Peter Robinson.
She said the situation was very grave.
“It is a sign of a complete breakdown in the working relationships within the Executive.
“Power-sharing only works effectively if you can have effective relationships between parties from different sides of the community and different parts of the political spectrum.”
Ms Villiers is chairing talks with Foreign Affairs Minister Charlie Flanagan at Stormont between the five largest parties in the North.
“I will be working and continuing to work with determination with the Prime Minister, with the Northern Ireland parties and with colleagues in the Northern Ireland Government to get a way through these crises and find a resolution to the hugely important challenges we now face.”
She added: “We did not think the circumstances will justify suspension, that has not changed and obviously suspension would not resolve the two big problems we face, implementation of the Stormont House Agreement and the presence of paramilitary organisations.
“The only way those problems are going to be resolved are through intensive cross-party talks.
“I think time is very short because of the seriousness of the situation, I think that today’s events make the situation much more serious.”
“Paramilitaries were never justified, they need to disband ... there is more that can be done to work towards the day when those organisations are a bit of Northern Ireland’s past, not its present.”