The Drug Enforcement Administration (DEA) operates a massive secret government database that tracks the movement of motorists across the country, documents reveal.

The documents, obtained by the American Civil Liberties Union through the Freedom of Information Act, cast further light on the scope of government surveillance and raise significant privacy concerns, the organization says.

At issue is the DEA’s national license plate reader program, which began aimed at vehicles in states along the Mexico border, ostensibly to fight drug trafficking.

The Wall Street Journalreported Monday:

The DEA program collects…