NEW YORK (AP) — Chicago and three other cities are suing the federal government to stop the proliferation of easy-to-assemble guns that require no serial numbers or background checks.

The lawsuit filed Wednesday in Manhattan federal court asks a judge to stop the government from letting gun parts that can easily be converted to functioning weapons be distributed without restrictions. The lawsuit was brought against the Justice Department and the Bureau of Alcohol, Tobacco, Firearms and Explosives by the cities of Chicago; Syracuse, New York; Columbia, South Carolina; and San Jose, California.

A message seeking comment was sent to the Justice Department. An ATF spokesperson said the agency doesn’t comment on litigation.