Donald Trump took up the criticism of MSNBC host Chris Matthews, who, during coverage of the attacks in Boston on Monday, wondered if it could be the work of domestic terrorists. "Normally domestic terrorists, people, tend to be on the far right. Though that’s not a good category, just extremists, let’s call them that," Matthews said.In response, Trump tweeted on Tuesday:[embedtweet id="324165224502534145"][embedtweet id="324167784118505474"][embedtweet id="324167991963041792"]Matthews' remarks had been picked up by a number of conservative news sites, who took issue with the characterization.