A top GOP donor says he won't write another check to Republicans until they support an assault weapons ban

Nikolas Cruz killed 17 people at Mary Stoneman High School with a legally purchased AR-15 rifle

Mourners stand during a candlelight vigil for the victims of Marjory Stoneman Douglas High School shooting in Parkland, Florida on 15 February 2018. (RHONA WISE/AFP/Getty Images)

A major Republican donor issued a remarkable ultimatum on Saturday, vowing to withhold money from GOP candidates unless they support a ban on selling military-style guns to civilians.

"It's the end of the road for me," Al Hoffman Jr., a prominent Florida real-estate developer, told The New York Times. "For how many years now have we been doing this — having these experiences of terrorism, mass killings — and how many years has it been that nothing's been done?"

Hoffman's comments came just days after a gunman opened fire on the Marjory Stoneman Douglas High School in Parkland, Florida, killing 17 people and renewing an impassioned national debate on gun control.

The suspected shooter, 19-year-old Nikolas Cruz, was armed with a legally purchased AR-15, one of the most popular semi-automatic rifles in the US.

That particular rifle is a recurring element in America's deadliest mass shootings, and was used in some variation by the perpetrators of recent massacres in Las Vegas, Nevada; Sutherland Springs, Texas; Orlando, Florida; and Newtown, Connecticut.

Like other semi-automatic firearms, commonly referred to as "assault weapons," the AR-15 was previously banned under a 1994 law that lapsed in 2004.

Gun-control activists have long called for Congress to reinstate the federal assault weapons ban, but Republican lawmakers staunchly refused to do so.

"Enough is enough!" Hoffman told The Times, adding that he hoped to start a movement within the Republican Party. "I will not write another check unless they all support a ban on assault weapons."

Hoffman has previously donated millions to Republican candidates such as ex-Florida Gov. Jeb Bush and former President George W. Bush.

The Florida school shooting prompted survivors and activists to mobilise on Saturday, unleashing torrents of anger at lawmakers, the National Rifle Association, and President Donald Trump for lax gun-control regulations.

"To every politician who is taking donations from the NRA, shame on you," Emma Gonzalez, a student who survived the Florida shooting, said in an impassioned speech at a gun-control rally in Fort Lauderdale on Saturday.

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