(CNN) - Sen. John Ensign, R-Nevada, told CNN Sunday it was "irresponsible" for President Obama to have been seen "laughing and joking" with Venezuelan President Hugo Chavez at the Summit of the Americas on Friday.
"This is a person who is one of the most anti-American leaders in the entire world," Ensign told CNN's John King on State of The Union. "He is a brutal dictator and human rights violations are very, very prevalent in Venezuela. And you have to be careful."
"When you're talking about the prestige of the United States and the presidency of the United States, you have to be careful who you're seen joking around with," he also said.
Chavez - whose anti-U.S. rhetoric has included calling former President George W. Bush the devil - announced Saturday he is considering naming an ambassador to the United States, signaling a potential shift in the tense relations between the two nations.
Speaking to reporters Sunday in Port of Spain, Trinidad and Tobago, Obama brushed aside criticism of the appearance, saying, "It's unlikely that as a consequence of me shaking hands or having a polite conversation with Mr. Chavez that we are endangering the strategic interests of the United States."
"Even with the imaginative crowd, I think that you would be hard pressed to paint a scenario where US interests would be damaged as a consequence of us having a more constructive relationship with Venezuela," he said.
Also appearing on CNN, Minnesota Sen. Amy Klobuchar, a Democrat, downplayed the moment between Obama and the Venezuelan leader, saying, "all the president did was shake his hand like George Bush [did]."
"What the president is doing here at the summit of the Americas: he is reaching out to all of these countries like he did at the G20 [Summit], I think very effectively," Klobuchar also said.
In the interview with CNN, Ensign was also sharply critical of the Obama administration for releasing previously classified CIA memos outlining Bush-era interrogation techniques.
"What the president has done is he has sent a fear throughout the intelligence community that they could be prosecuted in the future," Ensign said. "And that is exactly the kind of fear that paralyzed the intelligence community prior to September 11. I think America is less safe because of the release of these memos," he said.
The memos, written by then-lawyers for the CIA and Justice Department officials, said interrogation tactics such as waterboarding, sleep deprivation and slapping did not violate laws against torture when there was no intent to cause severe pain.