The Trump campaign is suing three Iowa counties over their absentee ballot request forms, marking the latest effort to go after states and localities that seek to make it easier to vote by mail this fall.

According to The Associated Press, the campaign is arguing that the mail-in ballot applications for Woodbury, Johnson and Linn county residents violate a directive from Iowa Secretary of State Paul Pate (R) that stipulated the forms must be completely blank when they're sent out.

The applications sent by those three counties reportedly had some information filled in for recipients. The counties argue that sending blank applications could disenfranchise voters who do not know their voting pin or driver's license number.

Johnson and Linn counties lean Democratic, while Woodbury leans Republican, the AP noted.

President Trump has a slight edge over former Vice President Joe Biden in Iowa, according to recent polls. A RealClearPolitics average of recent surveys shows Trump with a less than 2 percent point advantage over Biden, who will formally accept the Democratic Party's presidential nomination later this week. Trump won Iowa handily in 2016, defeating then-Democratic nominee Hillary Clinton by about 10 percentage points.

A Monmouth University poll released earlier this month showed Trump leading Biden, 48 percent to 45 percent, among registered voters in Iowa, a lead that falls within the margin of error for the survey.

The Trump campaign has sued a number of states for their voting rules as more election officials respond to increased demand for mail-in voting during the coronavirus pandemic.

On Tuesday, the Trump campaign filed a lawsuit against New Jersey after Gov. Phil Murphy (D) issued an executive order mandating that every registered voter in the state receive a mail-in ballot as a safety precaution amid the COVID-19 pandemic. Voters would still be allowed to cast their ballot in-person.

The Trump campaign filed a similar lawsuit against Nevada, where lawmakers passed a bill along party lines aimed at expanding mail-in voting before the November elections. The measure was signed into law by Gov. Steve Sisolak (D).

Trump has criticized mail-in voting in recent weeks, claiming without evidence that it could potentially lead to widespread fraud on Election Day.

The president and first lady Melania Trump both requested mail-in ballots for Florida's congressional primary, which was held on Tuesday.