Dave Graham and Matt Spetalnick

WASHINGTON/MEXICO CITY (Reuters) -The Biden administration has made a final decision to exclude the governments of Cuba, Venezuela and Nicaragua from the Summit of the Americas, people familiar with the matter said, despite threats from Mexico’s president to skip the gathering unless all countries in the Western Hemisphere were invited.

This decision was made after weeks of intensive deliberations. If Andres Manuel Lopez Obrador, the Mexican president, and other leaders decide not to attend, it could lead to an embarrassing boycott at this U.S.-hosted event in Los Angeles.

U.S. officials determined that concerns about human rights and lack of democracy in the three countries, Washington’s main antagonists in Latin America, weighed too heavily against inviting them, a Washington-based source said late on Sunday.

Recent weeks have seen the exclusion of Nicaragua and Venezuela, both leftist-led by Venezuela.

But with President Joe Biden due to open the summit on Wednesday, final word on Communist-ruled Cuba rested on whether to invite a lower-ranking representative in place of the island’s president, U.S. officials said.

Cuban President Miguel Díaz-Canel said last month he would not go even if invited, accusing the U.S. of “brutal pressure” to make the summit non-inclusive. Cuba was present at the previous summits.

Bloomberg News reported first the U.S. announcement. A request to comment was not received by the White House.

Mexico’s leftist president has said he was waiting for Biden to make a decision before announcing whether he would go. Lopez Obrador may follow Lopez Obrador’s lead Monday morning at regular news conferences.

Although Lopez Obrador thought that Cuba would be able to play a minor role in the negotiations, it was ultimately rejected by one source. Cuban activists from civil society were invited.

The U.S. has been unable to achieve its goal of using this summit as a way to restore relations with Latin America that were damaged by Donald Trump’s predecessor Biden.

After excluding Venezuelan President Nicolas Maduro from the presidency, the U.S. officials said that they are considering Juan Guaido’s role as opposition leader, perhaps virtually, at an upcoming side event.

Washington recognizes Guaido as Venezuela’s legitimate president, having condemned Maduro’s 2018 re-election as a sham.

Nicaraguan President Daniel Ortega (a Marxist guerrilla leader who was jailed alongside his rivals) is also barred from the summit.

Lopez Obrador not showing up could cause questions over the progress of discussions to curb migration at America’s southern border. This is a Biden priority.

Although most leaders indicated they would attend, the resistance of leftist-led countries suggests that many Latin Americans are not as willing to follow Washington’s example.

White House officials insist the invites ruckus won’t be over, and that summit success will come regardless of who goes.