MEXICO CITY (AP) - In an effort to control migration flows to its southern border, the government of El Salvador has introduced a $1,130 fee for travelers from 57 countries who are transiting through the nation's main airport. The move comes as the United States increases pressure on Central American countries to curb the influx of migrants crossing into its territory.

Since the end of October, citizens of various African countries, along with India, have been required to pay the airport improvement fee, as confirmed by El Salvador's aviation authority. Although the measure has been described as an "airport improvement fee" by officials, concerns have been raised about its potential to reduce migration. El Salvador's government has acknowledged a rise in travelers from these countries during the current year.

Aviation authorities in El Salvador have highlighted that the majority of passengers who are subjected to the fee are en route to Nicaragua through the commercial airline Avianca. Nicaragua, known for its relaxed visa requirements, serves as a transit point for migrants from Haiti, Cuba, and Africa who are attempting to reach the United States.

Earlier this year, an unexpected increase in Mauritanian migrants arriving at the U.S.-Mexico border raised eyebrows among U.S. officials. Investigations revealed that travel agencies and social media influencers were promoting a complex journey that took migrants from Mauritania to Nicaragua, with Avianca flights being used for the final legs of the trip.

Despite the implementation of the airport fee, El Salvador's aviation authority and immigration agency have not provided specific data on the number of migrants from these countries who have transited through the country thus far in 2021.

While a U.S. embassy spokesperson refrained from confirming whether the U.S. had requested the fee, it is speculated that President Nayib Bukele of El Salvador may benefit politically if he can assist the United States in controlling migration. During the previous administration of President Donald Trump, U.S. policy towards El Salvador was heavily focused on curbing migration, and Bukele faced little criticism from the U.S. as he consolidated his power. However, under President Joe Biden, the U.S. has been more vocal about concerns regarding Bukele's approach to human rights and democracy.

The U.S. State Department has raised allegations of "torture and other cruel, inhumane or degrading treatment or punishment, and other related abuses" against Bukele's government in its campaign against street gangs, as well as actions targeting journalists, activists, and critics.

Migration has once again become a key issue on the bilateral agenda between the U.S. and El Salvador. While the Biden administration has called on Central American nations to take more action to control migration, not all countries have responded positively. Guatemala, Costa Rica, Colombia, and Ecuador have collaborated with the U.S. to establish centers for migrants seeking asylum, family reunification, or temporary work permits. In contrast, Nicaragua has permitted numerous charter flights carrying Cuban and Haitian migrants heading towards the U.S., sparking warnings from the Biden administration.

As President Bukele faces criticism ahead of seeking reelection in 2024, the Biden administration has taken a more cautious approach, emphasizing that the debate surrounding the legitimacy of the election is a matter for Salvadorans. This stance differs from the strong condemnation of "anti-democratic behavior" during Guatemala's recent elections.

According to Pamela Ruiz, a Central America analyst for the International Crisis Group, Bukele's willingness to cooperate on immigration matters, including imposing a fee on certain nationalities, may be an attempt to mitigate international criticism. There are concerns that reduced levels of migration may ultimately lead to less scrutiny of the Bukele administration's actions.

The implementation of the airport fee in El Salvador underscores the ongoing challenges faced by countries in addressing migration flows, balancing political interests, and meeting the demands of the United States. The impact of these measures on migrants and their aspirations to reach the U.S. remains to be seen.

Associated Press writer Marcos Alemán in San Salvador, El Salvador, contributed to this report.