Story highlights Obama has appeared at two campaign stops for Clinton

Democrats hope Obama can convince the bloc of supporters who backed him to get behind Clinton

Washington (CNN) Eager to motivate his own base of supporters to vote in this year's contest, President Barack Obama will begin appearing in more advertising for Hillary Clinton, the White House said Tuesday.

Speaking a day after the first presidential debate, Press Secretary Josh Earnest said Obama would ramp up his role in the 2016 race as Election Day nears.

"I think through October, the President will be increasing his involvement in this race, and that doesn't just mean through travel," Earnest said. "That also means that the President will feature more prominently in the advertising efforts of Secretary Clinton and Democrats across the country."

Earnest said the ads would appear on television, radio and online. A message left with the Clinton campaign about the spots, including how much money would be spent on them, was not immediately returned.

Obama has appeared at two campaign stops for Clinton, and further stops are expected to be announced in the coming days. Both Vice President Joe Biden and First Lady Michelle Obama are making campaign stops for Clinton in Pennsylvania this week.

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