MEXICO CITY — Indigenous rebels of Mexico’s Zapatista movement complained Tuesday that the Mexican government has made it hard for them to get passports to attend meetings in Spain to mark the 500th anniversary of the 1519-1521 conquest of Mexico.

Rebel leader Subcomandante Galeano, who used to be known as Marcos, said officials had told some of the Zapatistas they didn’t have the right documents to obtain passports.

President Andrés Manuel López Obrador ordered officials Tuesday to resolve the problem, saying, “Nobody should be limited, much less our Indigenous brothers.” The first part of the delegation set out by boat in May to “invade” Spain.

That delegation has already reached Portugal’s Azores islands and will head to Vigo, Spain. The other part of the delegation was to fly to Europe, but ran into problems getting passports.

The Zapatistas have said they hope to be in Madrid by Aug. 13, the date that marks 500 years since Mexico City was captured from the Aztecs by the Spaniards and their Indigenous allies.

Galeano has said that once in Spain, the group will release the message: “The invasion has started.”

The Zapatistas have made no mention of demanding any apology for the invasion 500 years ago. That is unlike the Mexican government, which has asked Spain to apologize for the brutal conquest that wound up killing millions of Indigenous people.

Far from seeking a hostile encounter, the Zapatistas said, “If we manage to land and embrace with words those who are in the struggle there, who resist and rebel, then there will be a party.”

“We are going to tell the people of Spain two simple things,” the Zapatistas said in a previous statement. “One, they did not conquer us; we are still here resisting, in rebellion. Second, they do not have to ask that we forgive them for anything.”

The Zapatistas led a brief armed uprising to demand greater Indigenous rights in 1994, and since then have remained in their “autonomous” townships in the southern state of Chiapas, refusing government aid programs.