A Texas GOP lawmaker told Beto O'Rourke that his 'AR is ready for you' after the 2020 Democrat called for stricter laws on assault weapons

Screenshot/ABC News

Beto O'Rourke during the Democratic Debate on Thursday, September 12, 2019.

• A Republican lawmaker told 2020 Democratic candidate Beto O'Rourke that his "AR is ready" after O'Rourke spoke of a mandatory assault weapon buyback program during Thursday night's democratic debate in Houston, Texas. 
• In response to a question on gun control, O'Rourke said: "Hell yes, we're gonna take your AR-15, your AK-47." 
• Texas GOP Representative Briscoe Cain did not take kindly to the proposal and tweeted his displeasure. His tweet has since been removed. 
• O'Rourke screenshotted Cain's tweet and called it a "death threat." 
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A Texas GOP lawmaker responded to 2020 Democrat Beto O'Rourke's calls for stricter gun control on Thursday, writing on Twitter that his "AR is ready," referencing the semi-automatic rifle widely associated with mass shootings in the US.

O'Rourke participated in the latest round of debate against remaining Democratic candidates seeking the nomination for the upcoming presidential election Thursday night, and delivered an impassioned promise to tighten gun legislation if he is elected.

During the debate, which took place in his home state of Texas, O'Rourke cited tragedies such as the Odessa mass shooting last month which left seven people dead and 21 others injured, as reasons to tighten gun laws in the US.

In response to a question on his previous statements in favor of a mandatory assault weapon buyback program, O'Rourke said he wants to prevent weapons used in war from getting into the hands of civilians. 

"If it's a weapon that was designed to kill people on a battlefield ... Hell yes, we're gonna take your AR-15, your AK-47," he said to roaring applause from the audience.

"We're not going to allow it to be used against our fellow Americans anymore."

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Republican Representative Briscoe Cain did not take kindly to O'Rourke's proposal and tweeted his displeasure. 

"My AR is ready for you Robert Francis," Cain wrote, referring to O'Rourke's legal first and middle name. 

The tweet has since been removed. 

O'Rourke screenshotted the tweet, and called the message a "death threat." 

"This is a death threat, Representative. Clearly, you shouldn't own an AR-15-and neither should anyone else." 

Cain responded shortly after with another screengrab, calling O'Rourke "a child." 

O'Rourke's campaign is now selling t-shirts with his contentious slogan online.