Mr David Trimble has said he will resume office as Northern Ireland's First Minister only when the issue of decommissioning is fully resolved. He was speaking at Thiepval in western France before a commemoration of the 85th anniversary of the Battle of the Somme.
The Ulster Unionist leader said he had resigned as First Minister to ensure that the Good Friday agreement would be implemented in full.
"If you sit back hoping the IRA will disarm they won't. The only way the IRA moves is under pressure," he said.
Mr Trimble said that three years after the inauguration of the Northern Ireland Assembly there had been no real progress on decommissioning weapons. It was now up to the governments in London and Dublin to exert pressure on republicans.
"It is because I can no longer have any confidence in the unfulfilled promises of republicans that I have now ceased to be First Minister of Northern Ireland. I am prepared to resume that office but only if we see this issue resolved," he said.
The Northern Ireland Secretary, Dr John Reid, said the Somme symbolised more powerfully than anywhere else on earth the tragedy and futility of attempting to solve conflicts through violence. He said all sides must redouble their efforts if they were to secure a more peaceful and prosperous future for the North. "There is no inevitability about the failure of any aspect of the Good Friday agreement." After attending the main Somme Commemoration yesterday morning, Mr Trimble and Dr Reid went on to a second ceremony at the Ulster Tower in Thiepval.
During the afternoon ceremony to remember members of the 36th (Ulster) Division who died at the Somme, Mr Trimble's reduced status became apparent. He had been due to speak the exhortation but because he was no longer First Minister Dr Reid took his place.
Mr Trimble did not mingle with the crowd at either ceremony but he appeared relaxed and cheerful as he chatted to Dr Reid.
Many of those at Thiepval yesterday were members of the Orange Order and some expressed hostility towards the UUP leader.
Among the others in attendance were the Northern Finance Minister, Mr Mark Durkan, and PUP Assembly member Mr Billy Hutchinson.
More than 5,000 members of the 36th (Ulster) Division died during two days in action at the Somme in 1916. Built in 1921, the Ulster Tower is modelled on Helen's Tower at Clandeboye, Co Down.
Many of those attending yesterday's ceremony, including all Orange Order representatives, went on to lay wreaths at a nearby memorial to members of the 16th (Irish) Division, which was composed mainly of Catholics from Southern Ireland.