Irish Prime Minister Bertie Ahern (search) is expected to be at the White House to celebrate St. Patrick's Day (search) with President Bush, but Northern Ireland politicians aren't invited.

Setbacks in the peace process are a factor in the decision, Bush administration officials suggested Thursday.

The White House hasn't commented publicly on the matter. But in a break with tradition, Sinn Fein leader Gerry Adams (search) as well as other leaders in the peace process were not expected to be on the guest list when Ahern presents a traditional bowl of shamrocks to Bush on the March 17 ceremony.

Sinn Fein (search) is allied with the outlawed Irish Republican Army, which was recently implicated in the robbery of a Belfast bank and other crimes in Northern Ireland. The IRA has denied all the accusations. Sinn Fein says it wasn't involved, either.

But last month, the Irish government publicly identified three of Sinn Fein's top figures — including Adams — as members of the IRA command. The government's declaration signaled it no longer would go along with Adams' argument that his party should not be held accountable for IRA actions

Sinn Fein has been attending St. Patrick's Day events in Washington since 1995, when then-President Clinton sought to promote the peace process by inviting those involved. But the crimes and recent reluctance by the IRA to give up its weapons as part of the peace process have created new tensions.

Rather than singling out Sinn Fein, the White House was expected to go ahead with the ceremony without inviting any of the Northern Ireland parties to attend the usual reception.

At issue in the long drawn-out peace process is a plan designed to restore a Catholic-Protestant administration for Northern Ireland, the core goal of a 1998 peace accord for the British territory.