US officials are wary of dealing with Sinn Fein in the wake of alleged IRA links with rebels in Colombia, a US State Department source warned.
The warning comes from Richard Haas, a State Department official who monitors Northern Ireland.
The US doubt about Sinn Fein comes after allegations that the IRA has provided training to the Revolutionary Armed Forces of Colombia, or FARC.
Mr Haas has called on Sinn Fein to co-operate with the North's police force.