Cuban President Raul Castro’s snubbing of President Barack Obama upon his arrival in Havana didn’t escape the notice of GOP front-runner Donald Trump.

Wow, President Obama just landed in Cuba, a big deal, and Raul Castro wasn't even there to greet him. He greeted Pope and others. No respect

— Donald J. Trump (@realDonaldTrump) March 20, 2016

Trump told a Palm Beach, Fla., audience why he thinks Obama’s trip is pure “amateur hour.”

“Here’s how a thing like that is supposed to work. Number one, he has his people call up and say ‘Who’s going to be greeting the president?’ If they say ‘nobody’ you don’t go until somebody’s there because you don’t want to look like a fool,” explained Trump, mincing no words in explaining how diplomatic etiquette works.

The president’s move to lift trade embargoes on the communist island have not been without controversy, and neither has his ‘historic’ trip to Cuba. Over 200 marched and protested in Miami’s Little Havana Sunday in a staunch display of disagreement over the president’s brazen move, and dissidents in Cuba were arrested in advance of Obama’s arrival.

Trump’s rival Texas Senator Ted Cruz, whose father was a political prisoner in Cuba, wrote in Politico Magazine:

Meanwhile, political prisoners languishing in dungeons across the island will hear this message: Nobody has your back. You’re alone with your tormentors. The world has forgotten about you.

They will not be on TV, rubbing elbows with the Obamas or left-wing politicians like Nancy Pelosi. There will be no mojitos at the U.S. Embassy for them. Raul Castro denies their very existence.