Mexican President Andrés Manuel López Obrador confirmed Monday that he will not attend the Summit of the Americas in Los Angeles this week, citing concerns over the exclusion of leaders from Cuba, Nicaragua and Venezuela.

Why it matters: It's a blow to President Biden, who is seeking to reassert U.S. influence in Latin America and the Caribbean, which have become more closely tied to China in recent years, Axios' Marina E. Franco reports.

• The summit, which officially kicks off on Monday, is returning to the U.S. for the first time since it began in 1994.
• Squabbles over the guest list for weeks have overshadowed the summit's goal of fostering collaboration among the region.

What he's saying: "There cannot be a summit if all countries are not invited,” López Obrador said at a press conference, adding that Mexican Foreign Minister Marcelo Ebrard will instead represent the country’s government at the event.

• “Or there can be one, but that is to continue with all politics of interventionism.”
• By not inviting all American countries, Biden is "not respecting these countries’ sovereignty, their independence," López Obrador said.

The big picture: Some other leaders, including Bolivian President Luis Arce and Honduran President Xiomara Castro, had previously threatened to reject Biden's invitation to the summit, citing the possibility of leaders from Cuba, Nicaragua and Venezuela being excluded, Axios' Dave Lawler reports.

• López Obrador proposed last month that "everyone be invited" to the summit in order to further "the unity of all America."
• U.S. officials have cited human rights concerns and lack of democracy for not inviting the leaders of Cuba, Nicaragua and Venezuela, per Reuters.

What to watch: López Obrador said he hopes to visit the White House in July to talk to Biden about the "integration" of all American countries, with the goal of forming something similar to the European Union.

Go deeper: Summit of the Americas set to kick off as U.S. seeks to reassert influence