WASHINGTON  Burdened by lawsuits, criminal investigations and negative publicity stemming from its private security work in Iraq and Afghanistan, Blackwater Worldwide is being put up for sale, the company has announced.

Blackwater, which changed its name to Xe Services and brought in new management last year in order to remake its image, is pursuing a sale in part because that overhaul has failed to change perceptions of the company, most critically inside government, which is its main customer.

Erik Prince, the former member of the Navy Seals and heir to an automotive fortune who founded Blackwater, said in a statement given to The Associated Press late Monday that making the decision to sell the company was difficult, but that he no longer wanted to deal with the intense criticism the business has faced.

“Performance doesn’t matter in Washington, just politics,” Mr. Prince said.

A separate statement from the company’s headquarters, in Moyock, N.C., said, “Xe’s new management team has made significant changes and improvements to the company over the last 15 months, which have enabled the company to better serve the U.S. government and other customers, and will deliver additional value to a purchaser.”