The Prime Minister has urged Northern Ireland's political leaders to restore powersharing as soon as possible.
Theresa May held separate telephone conversations with DUP leader Arlene Foster and Sinn Fein’s Michelle O'Neill.
Dialogue has intensified in recent weeks between the two parties.
A Downing Street spokeswoman said:"In separate phone calls the Prime Minister made clear the importance of restoring a powersharing Executive to Northern Ireland as soon as possible and she recognised their continued leadership towards reaching agreement.”
"They discussed key outstanding issues that remain for both parties and the Prime Minister encouraged both leaders to come to an agreement soon in the interests of everyone in Northern Ireland.”
"The Prime Minister assured them both that the Northern Ireland Secretary would continue to work closely with the parties towards a successful outcome."
Formal talks between the two largest parties in Northern Ireland have yet to resume following a break for summer.