WASHINGTON -- Private-security contractor Blackwater Worldwide, which protects U.S. government officials in Iraq and faces scrutiny over its role in the shooting deaths of Iraqi civilians, has ramped up its lobbying representation on Capitol Hill.

Law firm Womble Carlyle Sandridge & Rice was tapped by the company, whose chairman is Erik Prince, a Holland native. They've been hired to lobby the government on contracting and other issues, according to the form posted online Tuesday by the Senate's public records office.

Womble Carlyle is the third lobbying firm to be hired by Moyock, N.C.-based Blackwater since October.The company has attracted considerable congressional scrutiny and criticism from the Iraqi government and human rights groups for its involvement in several dozen shooting incidents.

Federal prosecutors are investigating the Sept. 16 shooting deaths of 17 Iraqi civilians involving several Blackwater security guards. The company has maintained that its guards have always acted appropriately.

Prince, a former Navy SEAL, is a Holland native whose family fortune was made in the auto parts industry. His sister, Betsy DeVos, a former chairwoman of the Michigan GOP, is married to Dick DeVos, a Republican and Amway Corp. heir who unsuccessfully ran for governor in 2006.

In December, the Pentagon and State Department signed an agreement to give the military more control over Blackwater and other private security contractors, spelling out tighter rules, standards and guidelines.

Blackwater previously hired lobbyists Richard Cockrum and Gregory Hahn, according to disclosure forms. However, their forms did not indicate specific lobbying issues.

A phone call and e-mail to Blackwater spokeswoman Anne Tyrrell were not immediately returned.

Since 2006, Blackwater has been represented by C&M Capitolink LLC, a public affairs affiliate of Crowell & Moring LLP. The firm, which has been paid $300,000 from 2006 through the first half of 2007, has lobbied on ways Blackwater could help in border security efforts, among other issues, according to a disclosure report.

Blackwater has received federal contracts worth more than $1 billion, with the bulk of its earnings coming from the State Department, according to the House Oversight and Government Reform Committee.

Other military contractors -- such as DynCorp International Inc., which has a $4.6 billion U.S. military translation services contract in Iraq -- have also hired lobbyists to identify federal contracting opportunities.

Among the Womble Carlyle lobbyists representing Blackwater are: John Mashburn, former general counsel and policy director for Sen. Judd Gregg, R-N.H., who is the top Republican on the Senate Budget Committee; and Mark Harkins, who was chief of staff to Rep. Brad Miller, D-N.C., chairman of the Investigations and Oversight subcommittee of the House Science and Technology Committee.