Republican presidential nominee Donald Trump has sparked another firestorm of criticism over his comments at a rally in Wilmington, North Carolina, Tuesday, which many saw as a call to assassinate his rival, Hillary Clinton.

Donald Trump “Hillary wants to abolish—essentially, abolish—the Second Amendment. By the way, and if she gets to pick—if she gets to pick her judges, nothing you can do, folks. Although the Second Amendment people, maybe there is. I don’t know.”

In response to Trump’s comments, Connecticut Senator Chris Murphy tweeted, “Don’t treat this as a political misstep. It’s an assassination threat, seriously upping the possibility of a national tragedy & crisis.” California Congressmember Eric Swalwell, meanwhile, called for a Secret Service investigation, tweeting, “Donald Trump suggested someone kill Sec. Clinton. We must take people at their word. @SecretService must investigate #TrumpThreat.” Trump has denied the comments were a call to violence. His campaign issued a statement saying he was referring to the Second Amendment supporters’ “amazing spirit and … great political power.” On Tuesday night, House Speaker Paul Ryan called on Trump to clear up the comments.

Speaker Paul Ryan: “It sounds like just a joke gone bad. I hope he clears it up very quickly. You should never joke about something like that. I didn’t actually hear the comments; I only heard about those comments.”

Paul Ryan was speaking in Janesville, Wisconsin, at a victory news conference after he easily won his congressional re-election primary Tuesday. Donald Trump sparked controversy last week when he initially refused to endorse Ryan in his race.