Republican presidential candidate Donald Trump on Monday mocked rival Sen. Marco Rubio (R-FL) Monday, quipping that sweaty people shouldn’t be able to negotiate with foreign leaders like Russian President Vladimir Putin.

“When we get in with Putin we need people that don’t sweat. Let me tell you. No, it’s true. We gotta have people that don’t sweat,” Trump said of Rubio a rally in Greenville, South Carolina. “Can you imagine Putin sitting there and waiting for the meeting and this guy walks in and he’s like a wreck? No, you got to have Trump walk into that meeting folks, we’ll do very nicely.”

Trump mocked Rubio’s tendency to perspire on stage and said his rival had a “meltdown” at Saturday’s Republican presidential debate.

“No, he was standing right there, no, he was soaking wet, I’m telling you,” he continued. “He was wet. I say ‘What the hell’s going on over here?’ I thought he just came out of a swimming pool, he was soaking. I look, I said, ‘Wow, are you OK?’”

Trump has frequently mocked Rubio’s sweatiness in the past, reportedly sending him bottles of water over the summer with a note that read “since you’re always sweating.”