British Prime Minister Theresa May (L) talks with Irland's Prime Minister Enda Kenny at group photo session during an EU Summit at its headquarters in Brussels, Belgium, Oct. 20, 2016. (Xinhua/Ye Pingfan)

LONDON, Jan. 11 (Xinhua) -- British Prime Minister Theresa May and her counterpart in Dublin, Irish Taoiseach Enda Kenny, have discussed working together to find a solution to a crisis in Northern Ireland, Downing Street said Wednesday.

It followed the shock resignation of Sinn Fein's Martin McGuinness, deputy leader of the devolved assembly in Belfast.

The resignation of McGuinness means that unless Sinn Fein put forward a replacement within seven days, an election will be called to choose a new assembly for Northern Ireland. This has sparked fears that there could be a temporary return of home rule over Northern Ireland from Westminster

Under the terms of agreements in the region, McGuinness's departure meant Arlene Foster of the Democratic Unionist Party (DUP) automatically ceased to be first minister at Stormont.

In Belfast on Wednesday night, Sinn Fein party said they will not enter into negotiations. At crisis talks at Stormont which aimed at saving Northern Ireland's devolved institutions, Sinn Fein told Britain's Secretary of State for Northern Ireland, James Brokenshire, to call an election.

A Downing Street spokesperson said in a statement that May and the Taoiseach both recognized the difficulties and seriousness of the situation in Northern Ireland.

They also stressed how important it was to work together, with the Irish government and the parties of Northern Ireland, to find a solution.

The two leaders also spoke about how Brokenshire and Irish Minister for Foreign Affairs and Trade, Charlie Flanagan, will be working very closely together over the next few days and months to support the parties of Northern Ireland in finding a resolution.

Downing Street, in a statement, added: "The prime minister also said how important it was to make sure that Northern Ireland's voice and interests are heard as we prepare to leave the European Union and how the Northern Ireland secretary is fully committed to making this happen."

The statement added that it was still Britain's intention to hold a joint ministerial committee at the end of the month to bring the devolved regions together in getting the best deal for the whole of Britain.

The two prime ministers also agreed to maintain regular contact over the comings months.

In the House of Commons on Wednesday, May told MPs that she wanted to try to ensure that within the seven-day period before an election has to be called, a resolution to the political situation in Northern Ireland can be found so the assembly can continue to govern.

"We are treating this with the utmost seriousness, we are putting every effort into this," she said.

The row between Sinn Fein and DUP erupted over a controversial heating scheme which has overspent, with people in Northern Ireland facing having to pick up the cost estimated to be around 500 million pounds (611 million U.S. dollars).

The row evolved into a breakdown in trust between the two political parties.