The Ulster Unionist Party said in a statement: "For weeks now we have been calling upon the republican movement to tell us what they are going to do. We now hope they will tell us what they are going to do."
In London, there was a guarded response from the Conservative Party to the announcement.
Shadow Northern Ireland Secretary Mr Andrew Mackay said: "It would be right for us to comment on the proposals only when we have seen what the details are."