The ads are set to begin Friday in Florida, North Carolina, Ohio and Pennsylvania. | Getty Trump TV ads set to air in key battleground states

Donald Trump’s campaign began placing its first television advertising of the general election on Thursday: more than $3.5 million in broadcast ads in four traditional battleground states where Trump currently trails Hillary Clinton.

The ads are set to begin Friday in Florida, North Carolina, Ohio and Pennsylvania, and run through August 29. The full extent of the advertising is still unclear, but as of Thursday afternoon, Trump was set to spend $1.3 million in Florida, $775,000 in North Carolina, $675,000 in Ohio and $790,000 in Pennsylvania. That does not include cable-TV advertising, which was not yet available.

Trump’s campaign told POLITICO earlier this week the GOP presidential nominee would begin advertising in five states: the four where it began placing Thursday morning, but also Virginia.

Clinton – who, along with a super PAC supporting her candidacy, began advertising in all five of Trump’s target states for two months — currently leads Trump across those states, according to POLITICO’s Battleground States polling average. The Clinton campaign has, at least temporarily, suspended advertising in Virginia as she’s surged ahead there, though Virginia voters are still seeing the campaign’s ads as part of a national buy on NBC’s Olympic programming the past two weeks.

Clinton’s lead over Trump in the average stands at 5.2 points in Florida, 4 points in North Carolina, 2 points in Ohio, 9 points in Pennsylvania and 9.2 points in Virginia.

For some Republicans, the Trump ads are long overdue. Some of Trump's campaign staffers — including campaign chairman Paul Manafort and lead pollster Tony Fabrizio — spent much of the summer appealing to Trump to launch a paid-advertising campaign.

POLITICO's Shane Goldmacher and Alex Isenstadt contributed to this report.