U.S. Sen. Charles Schumer says he’s proposing legislation to require all gun buyers undergo a background check and increase penalties against states that don’t contribute names to the national background-check system.

Schumer, a Democrat, made the announcement Wednesday in Manhattan with New York City Mayor Michael Bloomberg, whose national gun-control coalition has been advocating such measures. The bill is still being drafted and doesn’t yet have any co-sponsors in the Republican-controlled House.

Financial penalties that are currently optional against states that don’t comply with the background check system would be made mandatory and raised from 3 percent of federal justice funds to 25 percent by 2018.

The bill would also close the so-called gun-show loophole that allows many gun show stands to sell firearms without background checks.