The U.S. Capitol is seen in Washington, U.S., March 26, 2019. REUTERS/Brendan McDermid

WASHINGTON (Reuters) - Lawmakers in the U.S. House of Representatives said on Thursday they have sent letters seeking documents and information from three companies responsible for detaining illegal immigrants arrested by U.S. immigration agents.

The House Oversight Committee and its House Subcommittee on Civil Rights and Civil Liberties sent letters to CoreCivic Inc CXW.N, Geo Group Inc GEO.N and DC Capital Partners LLC seeking information about the facilities they operate under contract from the U.S. government.

“The committee is investigating the Trump administration’s rapidly increasing use of for-profit contractors to detain tens of thousands of immigrants, including a troubling series of reports of health and safety,” Representatives Elijah Cummings and Jamie Raskin wrote in the letters.

The two Democrats said the Trump administration had “dramatically escalated” spending on contracts with for-profit companies that operate detention centers.

Comprehensive Health Services, a firm owned by DC Capital Partners, has received $545 million in Department of Homeland Security contracts to operate the Homestead Shelter in Florida since the start of 2018, they said in a statement.

GEO Group received $300 million in new contracts from Immigration and Customs Enforcement (ICE) in 2017, up $100 million from the previous year, and received $342 million in 2018. CoreCivic received $135 million in ICE awards in 2017, up $36 million from the previous year, and obtained nearly $141 million in contracts in 2018, they said.

In a separate letter to ICE, the two lawmakers asked for copies of the contracts with the three companies and documents detailing how ICE ensures that contractor-operated detention centers comply with standards set by the Department of Homeland Security.