MADISON, Wis. (AP) — A conservative group partially funded by the billionaire Koch brothers has launched a new $1.6 million television and digital ad campaign in Wisconsin targeting Democratic U.S. Sen. Tammy Baldwin.

The Freedom Partners Chamber of Commerce launched a pair of ads Thursday attacking Baldwin on taxes. One spot claims Baldwin supported $5 trillion in tax hikes on income, sales and energy. Another features the president of Northwest Builders Inc. in Rice Lake criticizing Baldwin, saying she's done nothing to help "working people like us."

Wisconsin Democratic Party spokesman Brad Bainum calls the new ads "dishonest smear attacks" from "out-of-state special interests."

He says Baldwin supports tax cuts for working families.

Delafied businessman Kevin Nicholson and state Sen. Leah Vukmir are running in the Republican primary to challenge Baldwin.