Rep. Mark Kirk (R) announced Monday that he raised more than $1.6 million during the third quarter, his first full quarter as a Senate candidate, more than doubling his second-quarter money haul.

Though he is known for his prolific fundraising abilities, Kirk’s relatively low $590,000 second-quarter total raised eyebrows among some in his party.

But Kirk’s campaign said he raised $1.5 million after he announced his bid July 20. He ended September with $2.3 million in cash on hand.

Former Chicago Inspector General David Hoffman (D) announced he had loaned his own campaign $500,000 and ended last month with more than $900,000 in his campaign account.

An aide for state Treasurer Alexi Giannoulias, the frontrunner in the Democratic primary, said the campaign was not ready to release its third-quarter fundraising totals yet. Giannoulias announced at the end of June, however, that he had almost $1.7 million in the bank.

The other Democrat in the race, former Chicago Urban League President Cheryle Robinson Jackson, has not released her totals so far.