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Story highlights

The Hillary Clinton campaign will spend an addition $1.5 million in Iowa and $2.6 million in New Hampshire on ads

Recent polling has shown Vermont Sen. Bernie Sanders closing in -- and at times passing -- Clinton in those two states

(CNN) —  

Hillary Clinton’s presidential campaign plans to spend more than $4 million reserving ad time in Iowa and New Hampshire throughout September and October, aides said Thursday.

Facing stepped up questions about her ongoing email controversy and the prospect of Vice President Joe Biden getting in the race, the campaign will spend $1.5 million reserving ad time in Iowa, the aides said, and will spend an additional $2.6 million in New Hampshire.

The Iowa ad buy will focus on the Des Moines and Cedar Rapids media markets, while the New Hampshire one will be in the Boston, Manchester, New Hampshire and Burlington, Vermont, media markets.

Clinton became the first top-tier candidate to hit the airwaves when the campaign made a $2 million ad buy for five weeks starting in August. Thursday’s ad buy was in addition to that and will focus on introducing Clinton to voters and conveying how her presidency would build on her life’s work.

RELATED: Highlights from the 2016 money wars

One ad – “Family Strong” – focuses on how Clinton’s mother, Dorothy, made her into the woman she is today.

“When I think about why I’m doing this, I think about my mother, Dorothy,” Clinton says in the ad. “I think about all the Dorothys, all over America who fight for their families, who never give up. That’s why I’m doing this, that’s why I’ve always done this, for all the Dorothys.”

The other ad focuses more on Clinton’s career highlights, including her work at the State Department and the White House as well as being a grandmother.

Recent polling has shown Vermont Sen. Bernie Sanders closing in – and at times passing – Clinton in Iowa and New Hampshire. Clinton aides, however, said Thursday that they remain confident in the state of the race.

Joel Benenson, Clinton’s top campaign pollster, said that the race is “fundamentally unchanged from where we would be before” polls showed Sanders up in New Hampshire.

“We always said there would be a tight race in New Hampshire,” Benenson said. “We see this race as kind of where we expected it to be, nip and tuck all the way to the primary.”

RELATED: Would Hillary Clinton be this bold today?

Republicans celebrated the fact Clinton was spending more on ads on Friday, arguing that it was another sign Clinton was “hitting the panic button” on her campaign.

“The Clinton campaign tried this approach before, only to see their lead over Bernie Sanders collapse in Iowa and disappear altogether in New Hampshire. It didn’t work then and it won’t work now,” said Michael Short, spokesman for the Republican National Committee.