WASHINGTON — Republican and Democratic lawmakers who remain bitterly divided over expanding gun-control measures are banding together to demand that federal agencies comply with existing ones, after reports indicated that the gunman who killed 26 people in a church shooting in Texas should have been prevented from buying a firearm.

The Senate’s second-highest-ranking Republican announced Tuesday that he was planning to file legislation aimed at forcing federal agencies to upload required information about infractions into NICS – the National Instant Criminal Background Check System – and incentivizing state governments to do the same.

“Their record of compliance is lousy, it’s lousy,” Sen. John Cornyn, R-Texas, complained on the Senate floor, describing the numbers of reports being filed as “staggeringly low.”

Cornyn was citing NICS statistics from late 2016 that showed many agencies, including many branches of the military, have reported zero felonies, domestic violence misdemeanors or restraining orders, indictments or other areas of concern to the NICS database.

Sen. Jeff Flake, R-Ariz., also announced Tuesday that he was joining forces with Sen. Martin Heinrich, D-N.M., “to prevent anyone convicted of domestic violence – be it in criminal or military court – from buying a gun,” Flake tweeted Tuesday.

President Trump, who is traveling in Asia this week, has been silent on the proposals. His son, Donald Trump Jr., responded to Flake’s effort by ridiculing it Tuesday, tweeting that Flake’s bill was “incredibly proactive considering that law has been on the books since the mid-’90s.”

But the senators’ complaint is that the federal agencies have not been complying with the law.

While it is not clear how many incidents have been omitted from the NICS database, lawmakers were convinced that the Texas gunman could not be an isolated case.

“This is only one example of repeated and frequent failures to report required convictions,” said Sen. Richard Blumenthal, D-Conn. Blumenthal sent a letter Tuesday to Defense Secretary Jim Mattis requesting a full accounting of how the Pentagon turns over such information to the FBI, as well as how the military prosecutes domestic violence cases.