U.S. immigration officials have barred a senior American-based representative of Sinn Fein from traveling back to the United States after a trip to Ireland because she violated her visa restrictions, the Irish Republican Army-linked party said Saturday. Rita O'Hare, who has been Sinn Fein's senior lobbyist and organizer in the United States since 1998, was denied a visa to accompany Sinn Fein deputy leader Martin McGuinness on his visit next week to New York and Washington.Peter King, a Republican congressman from New York who is sympathetic to Sinn Fein, said U.S. officials were trying to "send a signal" to the group with the travel ban. On Saturday, McGuinness and O'Hare met U.S. Ambassador to Ireland James Kenny to seek a reversal of the ban. U.S. immigration officials say O'Hare is being punished because she violated the terms of a previous visa by traveling without authorization to Florida.