Top Senate Republicans have asked Homeland Security Secretary Janet Napolitano to clarify a set of proposed new regulations governing the detainment and deportation of illegal immigrants, expressing concern that they might circumvent existing law.

“These policy memoranda raise serious questions about whether the Department is actually complying with existing immigration laws governing the detention and removal of aliens,” Senate Minority Whip Jon Kyl (R-Ariz.) and National Republican Senatorial Committee Chairman John Cornyn (Texas) wrote Napolitano in a letter Tuesday. “Based on our review of these memos, we are concerned that these new policies would circumvent, rather than promote the enforcement of, immigration laws pertaining to illegal aliens.”

“We are concerned that your proposals appear to be inconsistent with Congress’s intent when it passed the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 (IIRAIRA), and also might reflect your Department’s intention to less than fully enforce existing immigration laws,” the letter continues. “We would like a clarification of your position on these new detention and detainer policies and how these policies fulfill DHS’s responsibility to enforce immigration laws as intended by Congress.”

Kyl, along with Arizona Sen. John McCain, has led GOP efforts for stiffer border control to stem illegal immigration. The issue has been front and center this election year, particularly after Arizona passed a controversial enforcement measure to combat illegal immigration. The Obama administration has since challenged the measure.