WASHINGTON — President Trump’s campaign more than doubled its spending over the past three months as the president worked to rev up the Republican base ahead of next month’s midterm elections through a series of rallies and online appeals.

The increased spending — much of which was done through an opaque new corporate entity set up by the campaign — was reflected in filings that the campaign’s committees were set to submit on Monday evening to the Federal Election Commission.

The filings showed that the campaign spent a total of $7.7 million from the beginning of July and to end of September — more than twice the $3.6 million spent in the preceding three months — according to a preview of the filings provided to The New York Times.

The campaign and two joint committees it formed with the Republican National Committee raised a total of more than $18 million in the last quarter, a slight increase over the preceding quarter.