The talks in Hillsborough on Thursday with Northern Ireland parties were "both frank and at times forceful", the Taoiseach, Mr Ahern, told President Bush yesterday.
During a lunchtime telephone conversation, Mr Ahern said the discussions had been valuable in ensuring that all parties were focused "on the task ahead", though he said the process was at "an extremely difficult stage".
He briefed the US President on the Irish and British governments' plans. Both Mr Ahern and Mr Blair insist that the mid-August timetable set down by the North's First Minister, Mr David Trimble, is too long.
Instead, the two leaders believe that a deal on decommissioning and the other outstanding issues must be agreed by the middle of July - just when the political temperature in Northern Ireland will be at its height.
President Bush, who is less interested in Northern Ireland than was his predecessor, former president Bill Clinton, said he would "keep in touch on the issue over the coming weeks".
Meanwhile, the chairman of the International Decommissioning Body, Canadian General John De Chastelain, is expected to file his latest report on the prospects of paramilitary decommissioning on Monday.
Gen De Chastelain met with Mr Blair, Mr Ahern, the Minister for Foreign Affairs, Mr Cowen, and Northern Secretary Dr John Reid during Thursday's talks in Hillsborough Castle.
During the half-hour conversation between Mr Ahern and Mr Bush, the President complimented the Government for its offer of increased aid to the fight against AIDS in Africa.
The decision by the Serbian government to send former Yugoslav president Mr Slobodan Milosevic to the International War Crimes Tribunal in The Hague was "a strong sign of commitment", said Mr Bush.
It "sends an unequivocal message to those people who were involved in the atrocities that were perpetrated during the Balkan conflict that they will be held accountable for their crimes", he told the Taoiseach.
