The leaders who brokered a peace deal for Northern Ireland in 1998 have marked its 20th anniversary by warning about new dangers for the region.

Former U.S. President Bill Clinton and ex-British Prime Minister Tony Blair joined Irish and Northern Irish politicians in Belfast to mark the breakthrough on April 10, 1998 that called an end to 30 years of sectarian violence in which around 3,600 people died.

But the collapse early last year of the power-sharing administration at the heart of that deal meant there was no devolved government to greet them – and little sign of the province’s Irish nationalists and pro-British unionists resolving the differences that have again divided them.