Ron Paul supporters boo Mitt Romney's son Josh Romney at Arizona Republican Party convention

PHOENIX, AZ -- Supporters for Congressman Ron Paul are causing trouble for the Mitt Romney camp.

On Saturday, they booed Romney's son, Josh Romney, during his speech at the Arizona Republican Party convention.

Paul is the only opponent that has continued campaigning for the GOP nomination despite Romney's commanding lead.

The Texas congressman's supporters have begun to flood state conventions, trying to win control of delegates for the national convention in August -- when Republicans officially nominate their candidate.