The Justice Department is seeking information about whether lawsuits by environmental groups hindered efforts to improve New Orleans levees (search), an effort the Sierra Club and Democratic lawmakers say is aimed at shifting blame for the massive flooding.

The request to federal prosecutors, sent in an e-mail earlier this week, followed harsh criticism of the Bush administration for its initial response to Hurricane Katrina and the breach in New Orleans' levees that sent floodwaters from Lake Pontchartrain (search) pouring into the city.

"Has your district defended any cases on behalf of the Army Corps of Engineers (search) against claims brought by environmental groups seeking to block or otherwise impede the Corps work on the levees protecting New Orleans? If so, please describe the case and the outcome of the litigation," said the communication, which was read to The Associated Press on Friday by Justice Department spokesman Brian Roehrkasse.

David Bookbinder, Sierra Club senior attorney, said the administration "is more interested in building a case to deflect blame than actually underscore what went wrong before, during and after the crisis."

Roehrkasse said the Justice Department is not seeking to deflect criticism of the administration. Rather, he said, the e-mail, which was first disclosed Friday in a story by the Jackson, Miss., Clarion-Ledger, was a response to a question from a committee in the Republican-controlled Senate.

The request came from the Senate Environment and Public Works Committee, committee spokesman Bill Holbrook said. The panel, led by Oklahoma Sen. James Inhofe, "wants to know what happened to prevent modernization of the levees," Holbrook said.

Some conservatives have complained that environmental groups have escaped blame for their opposition to levee projects. The Competitive Enterprise Institute posted on its Web site an article noting that "the opposition of environmental activist groups to building levees in the first place" has drawn little attention in the hurricane's aftermath.

It cited two groups, American Rivers and the Sierra Club (search), for their federal suit in 1996 to block an upgrade of 303 miles of levees in Arkansas, Louisiana and Mississippi. Most of those levees are on the Mississippi River and did not fail during Katrina.

Separately, an environmental lawsuit in 1977 stopped an Army Corps project designed after Hurricane Betsy in 1965 to protect New Orleans from storm surges.

New Jersey Sen. Frank Lautenberg, a Democrat on the Senate panel that asked about the lawsuits, said he believes the information sought by the Justice Department is part of a concerted effort by the administration to deflect criticism.

"The administration is obviously desperate to divert attention from their failure of leadership that followed this tragedy," Lautenberg said.