WASHINGTON (Reuters) - The Justice Department has been secretly gathering and storing hundreds of millions of records about motorists in an effort to build a national database that tracks the movement of vehicles across the country, the Wall Street Journal reported on Monday.

The newspaper said the main aim of the license plate tracking program run by the Drug Enforcement Administration was to seize automobiles, money and other assets to fight drug trafficking, according to one government document.

But the use of the database had expanded to include hunting for vehicles linked to other possible crimes, including kidnapping, killings and rape suspects, the paper said, citing current and former officials and government documents.

While U.S. officials have said they track vehicles near the Mexican border to combat drug cartels, it had not been previously revealed the DEA had been working to expand the database "throughout the United States," the Journal said, citing an email.

It said many state and local law enforcement agencies were using the database for a variety of investigations, the paper said.

It added it was unclear if any court oversaw or approved the program.

The Journal quoted Senator Patrick Leahy, the senior Democrat on the Senate Judiciary Committee, as saying the use of license plate readers "raises significant privacy concerns."

A spokesman for the Justice Department, which oversees the DEA, told the paper the program complied with federal law. "It is not new that the DEA uses the license-plate reader program to arrest criminals and stop the flow of drugs in areas of high trafficking intensity," the spokesman was quoted as saying.

(Writing by Eric Walsh; Editing by Peter Cooney)