A federal judge won’t block a controversial Trump administration initiative to share highly sensitive taxpayer information with federal immigration authorities, in hopes of tracking down undocumented immigrants and quickly deporting them out of the country.

A federal judge on Monday refused to block the Internal Revenue Service from sharing immigrants’ tax data with Immigration and Customs Enforcement for the purpose of identifying and deporting people illegally in the U.S.

The Department of Homeland Security can partner with the IRS to permit ICE to access taxpayer information to locate illegal immigrants, a judge ruled.