INDIANAPOLIS (AP) — Indiana is becoming a major battleground in the race for control of the Senate, with national Republicans and Democrats sending more cash this week to tea party favorite Richard Mourdock and Democrat Joe Donnelly.

Republicans, who must gain four seats nationally to take control of the Senate, are extending a run of attack ads for Mourdock this week. The Democratic Senatorial Campaign Committee, meanwhile, is spending $439,000 in the state in coming days on Donnelly’s behalf.