KENOSHA - Kenosha County's top administrator, facing federal charges of accepting illegal cash payments, announced Tuesday he will resign from office effective March 31.

County Executive Allan Kehl is scheduled for arraignment Friday in U.S. District Court in Milwaukee.

He was indicted last month for allegedly accepting $15,000 to $20,000 in illegal payments from Kenosha businessman Dennis Troha.

Kehl, whose current four-year term would end in 2010, previously said he would stay in office as the case moved through the court system.

But he released a statement to reporters and County Board members, saying he had found it "exceedingly difficult to focus on my duties as county executive to serve the best interests of county government.

"Therefore, effective March 31, 2008, I am resigning from the office of Kenosha County executive and I have no further comment," he said.

Prosecutors alleged that Kehl received individual cash payments of $5,000 each as "purported campaign contributions," but they exceeded legal limits and weren't reported on campaign finance forms.

Kehl is charged with one count of conspiracy carrying up to five years in prison and $250,000 in fines.

Troha was sentenced last week to six months of probation for illegal campaign donations.

He had pleaded guilty to two misdemeanor charges in July. Prosecutors recommended probation for Troha because he has cooperated with authorities, providing information that has led to indictment of three others.