The campaigns of U.S. Sen. Pat Roberts and the Kansas Republican’s primary challenger are sparring publicly over ethics issues, increasing the acrimony in their already contentious race.

Roberts executive campaign manager Leroy Towns filed a complaint last week with the Senate Ethics Committee against challenger Milton Wolf.

Wolf hasn’t yet filed a required financial disclosure form, despite a 30-day deadline.

But Wolf spokesman Ben Hartman said the challenger will file the form soon, within a grace period that’s typically given to new Senate candidates.

Wolf’s campaign accused Roberts of attempting to intimidate his challenger. Towns said Wolf is willing, in his words, to “make facts up.”

The 77-year-old Roberts is seeking his fourth, six-year term in the Senate. Wolf is a 42-year-old Leawood radiologist running as a tea party candidate.