Mexican President Enrique Pena Nieto walks with then-presidential candidate Donald Trump after a meeting on Aug. 31, 2016, in Mexico City.

Donald Trump's campaign raised $5 million on Aug. 31, the day of the Republican nominee's whirlwind trip to Mexico, the campaign said Thursday.

That marks about 5 percent of the $90 million raised by the campaign and its joint fundraising arm with the Republican Party during August. It was unclear if that sum was the campaign's biggest for a single day, but it has previously sent emails to supporters with fundraising goals of up to $2 million in a day.