Presumptive Republican presidential nominee Donald Trump on Wednesday said he will meet with the National Rifle Association about preventing people on a U.S. government terrorism "watch list" from buying guns following the massacre at an Orlando gay nightclub.

The NRA, a politically influential lobbying group that claims more than 4 million members and has played a key role in thwarting gun control legislation in the U.S. Congress, endorsed Trump on May 20. The New York real estate developer told an NRA convention that same day that he would protect the constitutional right to bear arms.

Trump in a November television interview he said he would support gun restrictions for someone on a "watch list" who is "an enemy of state."

The FBI maintains two terrorism "watch lists," a fairly limited "no fly" list barring people from flying to and from the United States and another larger list. Omar Mateen, the U.S.-born son of Afghan immigrants who killed 49 people at the Pulse nightclub in Orlando early on Sunday morning, was on that broader list at one time.

Presumptive Democratic presidential nominee Hillary Clinton has supported gun control efforts and said on Monday she was "bewildered" that congressional Republicans had blocked a Democratic effort to restrict gun sales to people on the watch lists.

Trump has accused Clinton of wanting to abolish the Second Amendment of the U.S. Constitution, which protects the right to "keep and bear arms."

The Trump campaign declined to provide more information about the NRA meeting. "We will send details at the appropriate time," campaign spokeswoman Hope Hicks said.

The NRA did not immediately respond to a request for comment on Wednesday. On Tuesday, the group said on Twitter that barring people on watch lists from buying guns is "ineffective, unconstitutional, or both."