QUITO, Ecuador — A plan by Ecuador to let the U.S. military use a Galápagos island for aircraft on anti-drug trafficking flights is drawing criticism that the agreement would damage the archipelago’s unique animal and plant life.

About 30 people protested outside the main government office in Quito on Monday, calling the plan a threat to the environment of the U.N. world heritage site as well as Ecuador's sovereignty. Protester Gloria Reinoso said she was concerned about the impact of the noise and infrastructure required to support a U.S. military presence.

Last week, Defense Minister Oswaldo Jarrín said San Cristóbal island could be a staging point for American aircraft flying surveillance missions aimed at stopping drug traffickers who transport illicit cargo by sea. Jarrín said flight crews would stay a week at most on the island and would be monitored by Ecuadorian authorities.

The United States Southern Command, which is responsible for U.S. military affairs in the region, did not immediately comment.

One analyst said little information is available about the plan for the archipelago in the Pacific Ocean, which is about 1,000 kilometers (620 miles) from the Ecuadorian coast. Charles Darwin developed his theory of evolution after studying the extraordinary diversity of species on the islands in the 19th century.

The United States had a base in the Galápagos during World War II and operated it without the involvement of Ecuadorian authorities.

Grace Jaramillo, a political scientist at the University of British Columbia in Canada, said more needed to be known about reasons for the recent plan with the U.S. military as well as the environmental costs for "our "touristic jewel."

"What are the benefits? How was it negotiated?" Jaramillo said.

Carlos Espinosa, an analyst at the Universidad San Francisco de Quito, said it would be better to stage anti-drug flights from the South American mainland so as to safeguard Galápagos ecosystems.

Another commentator, Farid Simon, gave a different view, saying that relatively brief stopovers by U.S. planes did not mean an airport in the Galápagos would become a military base.

“We have an obligation to contribute to the fight against drug trafficking,” Simon said.