Democratic gubernatorial candidate Steve Sisolak's campaign has placed a large television ad reservation for mid-September, the candidate's first major advertising expenditure since the run-up to the state's June primary.

According to documents filed with the Federal Communications Commission (FCC) on Monday, Sisolak's campaign will begin running ads in southern Nevada TV markets from September 11 through October 1. Sisolak's campaign declined to comment on the order.

According to the "market budget" listed on the forms filed with the FCC, the campaign is spending around $438,000 on the planned ads.

The ad reservations come as Sisolak's general election opponent, Republican Attorney General Adam Laxalt, has launched at least six television advertisements since the primary election in June. Laxalt's ads have largely focused on his biography, while others have attacked Sisolak for certain votes made through his position on the Clark County Commission and for supporting the "radical left."

Sisolak reported spending more than $6 million through the first half of 2018, largely on television advertisements in his bid to defeat Democratic primary rival and fellow Clark County Commissioner Chris Giunchigliani.

Laxalt, who heavily outraised primary competitors and won an easy victory in the state's June election, reported spending around $1.3 million during the first half of 2018.