Payday lenders warned Thursday that they would sue to stop the just-released Obama administration payday lending rule if it is not changed, as partisan lines began to form around the regulation with Republicans criticizing it and Democrats rallying behind it.

Speaking with reporters Thursday morning, Dennis Shaul, head of the Community Financial Services Association of America that represents payday lenders, said that the Consumer Financial Protection Bureau’s 1,300-plus page rule announced early Thursday was still being reviewed, but would face a legal challenge if it weren’t changed.