Focusing on a key gun issue, the Justice Department will offer states more than $20 million to strengthen the background checks designed to keep guns from being sold to potentially dangerous people.

States are critical to the National Instant Criminal Background Check System. They keep criminal histories and records of people barred from having guns because of domestic violence or for mental health reasons.

The $20 million would help fill information gaps by improving reporting to the national system on involuntary commitments to mental health facilities, felony convictions, misdemeanor convictions for domestic violence, domestic violence restraining orders and active criminal warrants.

Congress is debating whether to expand the background check system, which applies only to sales by federally licensed gun dealers, not private transactions at gun shows or online.