DES MOINES, Iowa (AP) — Campaign aides to President Barack Obama and Republican presidential candidate Mitt Romney say the candidates plan to stop in Iowa this month, in the weeks leading up to the party's national conventions.

Romney will headline a private fundraiser Tuesday in West Des Moines and a public event that hasn't been finalized. Obama aides said only that the Democrat would visit Iowa in August. Aides to the campaigns declined to be named because the campaigns haven't announced the visits.

It's Romney's third stop in Iowa since becoming the likely nominee. Obama, a Democrat, has been to Iowa four times this year.

The candidates and allied groups have spent more than $26 million on TV advertising in Iowa, among about a half-dozen states where polls show the race is tight.