Washington (CNN) Former Virginia Attorney General Ken Cuccinelli started Monday as acting director of the United States Citizenship and Immigration Services, putting a hardliner to the top of the agency that administers the nation's immigration system but drawing bipartisan criticism.

The moves come as President Donald Trump and the White House tries to crack down on the dramatic increase in number of migrants crossing the southern border.

"Together we will continue to work to stem the crisis at our southwest border," Cuccinelli said in a letter to USCIS employees. "We will also work to find long-term solutions to close asylum loopholes that encourage many to make the dangerous journey to the United States so that those who truly need humanitarian protections and meet the criteria under the law receive them."

L. Francis Cissna was ousted last month as director in the wake of a major shakeup this spring among the leadership at the Department of Homeland Security, which included the departure of Homeland Security Secretary Kirstjen Nielsen.

The announcement Monday prompted sharp criticism from both Democrats and Republicans.

Read More