Mr Bush's flight touched down at RAF Aldergrove airport outside Belfast on schedule just after 2.30pm and he travelled from there to Stormont.

The president was meeting Northern Ireland First Minister Peter Robinson and Deputy First Minister Martin McGuinness in Stormont Castle, while Prime Minister Gordon Brown and Taoiseach Brian Cowen were also attending.

Security was tight around Belfast in advance of the President's arrival and normal political business at Stormont's Parliament buildings was cancelled.

The Alliance Party, which holds only seven seats in the 108-member Northern Ireland Assembly, but which has been a vocal critic of the performance of the power-sharing Executive, complained about the disruption to proceedings.

But this was dismissed by Junior Minister Jeffrey Donaldson.

``I think it is unfair that there are some politicians who seem not to appreciate that the president of the largest democratic country in the world has come here,'' said Mr Donaldson.

``This is a great opportunity for Northern Ireland to press home the case for investment.

``It is an opportunity that should not be spurned.''

Today's political meetings were being held in Stormont Castle, near Parliament Buildings in the Stormont estate.

Former first minister Ian Paisley, who stepped down from office two weeks ago, was also due to meet the president at the venue.