The Department of Justice filed lawsuits Thursday against four states for refusing to issue undercover license plates to federal immigration officers.

The legal action targets Maine, Washington, Oregon and Massachusetts, all states with Democratic leadership. The lawsuits follow a letter sent from the DOJ earlier this month urging the four jurisdictions to provide confidential plates to federal agents.

The undercover license plates are intended for use by federal immigration officers and other Department of Homeland Security personnel during official operations. The DOJ argues that denying these plates interferes with federal law enforcement activities.

The four states have declined to issue the specialized plates, setting up a legal confrontation between state and federal authorities. The dispute represents another area of tension between the Trump administration and Democratic-led states over immigration enforcement policies.

The Justice Department's lawsuits seek to compel the states to provide the requested undercover license plates for federal agents operating within their borders.