LONDON — British Prime Minister Boris Johnson hailed "an historic time" for Northern Ireland ahead of a visit to the province on Monday to mark the reopening of its power-sharing government after three years of deadlock.

Johnson will meet newly appointed First Minister Arlene Foster and deputy First Minister Michelle O'Neill during his trip to Belfast.

"This is an historic time for the people of Northern Ireland," Johnson said in a statement ahead of his visit.

"The next decade will be an incredible time of opportunity for Northern Ireland and the whole of the United Kingdom as we come together to unleash the potential of our four nations," he added.

The devolved Northern Ireland assembly reopened on Saturday following three-years of political deadlock after rival pro-Irish republicans and pro-British unionist parties agreed to a new power-sharing deal with Brexit looming.

Democratic Unionist Party leader Foster was appointed as first minister, and effective head of government, while Republican Sinn Fein's O'Neill was elected as her deputy.

The region's devolved assembly at Stormont collapsed in January 2017 over a scandal caused by the runaway costs of a renewable energy scheme.

Its 90 members had since sat only for one-off sessions, with numerous rounds of acrimonious negotiations failing to reach a solution, leaving basic services unattended.

But they returned on Saturday after republicans and unionists struck a deal on Friday under the threat of a new regional election if they missed the latest deadline to reconvene on Monday. — AFP