U.S. Citizenship and Immigration Services officials focused on denaturalization were sent to offices nationwide, sources say.

The Trump administration is dramatically expanding an effort to revoke U.S. citizenship for foreign-born Americans as it works to curb immigration, according to two people familiar with the plans.

Over the past several months, U.S. Citizenship and Immigration Services, the agency within the Department of Homeland Security that’s responsible for legal immigration, has been sending experts to its offices around the country or reassigning staff members to focus on whether some citizens processed through those offices could now be denaturalized, these people said.

The goal of emphasizing naturalized citizens is to supply the office of immigration litigation with 100 to 200 possible cases per month, one of the people familiar with the plans said. Such cases have typically been very rare, involving people who concealed criminal histories or previous human rights violations during their application processes. The New York Times first reported the quota.