Mexico’s President Andres Manuel Lopez Obrador worked to "blackmail" President Joe Biden to include authoritarian leaders from Venezuela, Cuba and Nicaragua during this week’s Summit of the Americas in Los Angeles, said Sen. Bob Menendez, D-N.J., on Thursday.

In an interview with MSNBC on the third day of the summit, Menendez lobbed his accusation against the Mexican president. Lopez Obrador opted against attending the event, arguing that its importance was diminished without every country in the region present.

But Menendez, a vocal critic of Cuba and Venezuela in particular among Democrats, defended Biden’s decision not to include the two leaders as well as Nicaraguan President Daniel Ortega. Doing so, the senator said, sent the right message that the invitation was reserved for democracies.

“I think President López Obrador basically tried to blackmail President Biden into insisting countries that are not democratic, countries like Venezuela, Cuba, Daniel Ortega’s Nicaragua, that are dictators and despots, should have been invited to the summit,” Menendez said in the interview, adding that he applauds Biden for their exclusion.

Menendez’s remarks followed comments from Lopez Obrador a day earlier where he singled the senator out alongside other Cuban American senators Marco Rubio, R-Fla., and Ted Cruz, R-Tex., for upholding the decades-old U.S. embargo against Cuba.

“Those two gentlemen I understand them better because they’re Republicans," Lopez Obrador remarked at a press conference, referring to Rubio and Cruz. "But this gentleman, he’s in the Democratic Party," he said of Menendez.

Despite an initial warming of ties under the Obama administration, U.S. relations with Cuba cooled through the Trump administration and the stance has remained largely the same under Biden. Many Cuban Americans in the U.S. oppose relations with Havana’s communist government and they make up notable constituencies across the U.S.

Relations with Venezuela and Nicaragua are similarly poor. The Trump administration worked to oust President Nicolas Maduro from power in 2018 and heavily sanctioned the country. Ortega, Nicaragua’s President, has been a vocal critic of U.S. foreign policy and his government was sanctioned by the Biden administration in November 2021.

Cuba, Venezuela and Nicaragua all attended previous summits alongside American officials, but these took place outside the U.S.

In 2015, former President Barack Obama used the summit as an opportunity to meet with Cuba’s then-President Raul Castro as part of his opening to the island nation.

Three years later in 2018, the summit took place in Peru without Maduro’s presence because of his decision to launch elections early without any opposition parties present. Former President Donald Trump declined to attend, but former Vice President Mike Pence appeared in his place.