LOS ANGELES, United States (AFP) — President Joe Biden’s plan to reboot US engagement with Latin America — especially on critical topics like migration — took a hit after key partner Mexico snubbed a regional summit opening Monday in Los Angeles to protest Washington’s exclusion of three far-left countries.

What was meant to be a week-long showcase of cooperation risks becoming a display of division, underlining diminishing US clout over a region where Washington’s long-time economic and diplomatic influence faces a growing Chinese challenge.

A senior White House official confirmed that Cuba, Nicaragua and Venezuela were barred from the Summit of the Americas due to “lack of democratic space and the human rights situations”.

In response, Mexican President Andres Manuel Lopez Obrador said he too would stay away.

“You cannot have a Summit of the Americas if you do not have all the countries of the Americas attending,” Lopez Obrador announced, complaining of US “hegemony” and “lack of respect for nations”.

Although Foreign Minister Marcelo Ebrard will represent Mexico instead, the leftist populist leader’s absence will diminish the impact of a summit where US-Mexico relations are at the heart of major immigration and trade issues.

The White House downplayed the spat, saying Biden was sticking up for principles, but that there was no bad blood between the neighbours.

“We do not believe that dictators should be invited,” Press Secretary Karine Jean-Pierre told reporters.

However, she noted that Lopez Obrador was set to visit Washington in July and said Biden had not been blindsided. “He was aware” ahead of the Mexican president’s announcement.

In Havana, the communist Cuban Government issued a statement calling its exclusion “anti-democratic and arbitrary”.

Biden, who flies to Los Angeles on Wednesday, will be announcing numerous “deliverables” at the summit, Jean-Pierre said.

The agenda on Wednesday will focus on regional economic and health issues, then climate change on Thursday. Friday will be devoted to the surge of migration to the United States.