Colombia's claim to Peru for the possession of a river island on the common border is a consequence of a natural phenomenon due to changes in the course of the Amazon River that have caused the emergence of new formations and that will require meticulous diplomatic work for its solution.

The following are the keys to understanding the origin of this controversy in the triple border zone formed by the towns of Leticia (Colombia), Santa Rosa (Peru) and Tabatinga (Brazil).

(See: Peruvian government accused Colombia of air raid on Santa Rosa Island).

Creation of the district of Santa Rosa de Loreto

The Peruvian Congress unanimously approved on June 12 the "creation of the district of Santa Rosa de Loreto in the province of Mariscal Ramón Castilla in the department of Loreto, with its capital the town of Santa Rosa," which was published on July 3 in the official newspaper El Peruano. In response, Colombia submitted two protest notes on June 20 and July 3, requesting the reactivation of the Permanent Joint Commission for the Inspection of the Colombian-Peruvian Border (Comperif) because, according to the Ministry of Foreign Affairs,"Santa Rosa Island is a formation that emerged in the course of the Amazon River, after the only assignment of islands made between the two countries in 1929." Therefore, according to Colombia,"it has not been assigned to Peru" and is due to to carry out "a process of allocation by mutual agreement between foreign ministries." Peru responded on July 4 with another diplomatic note in which it rejected "the terms" of the two Colombian notes and reaffirmed "the legitimate rights of sovereignty over the integrity of our national territory." (See: ).

The matter moved from the diplomatic to the political arena on August 5, when President Gustavo Petro accused Peru of appropriating"a territory that belongs to Colombia" on the Amazon River, with the consequent responses from his Peruvian counterpart, Dina Boluarte. The Solomon-Lozano Treaty of 1922

Colombia and Peru invoke the "Treaty of Limits and River Navigation between Colombia and Peru", known as the Salomón-Lozan Treaty, signed in Lima on March 24, 1922 , which establishes"the boundary line" between the two countries, which includes"the 'thalweg' of the Amazon River to the boundary between Peru and Brazil".

The 'thalweg' is a method used to determine boundaries on international rivers and is defined by the median line of the navigable channel of a watercourse.

This treaty was ratified by both countries in early 1928, the year in which its technical application began.

The Joint Demarcation Commission

The Joint Commission in charge of demarcating the limits established in the 1922 Treaty met in Iquitos (Peru) in October 1928, and in February and November 1929 to define the line where the 'thalweg' of the Amazon and Putumayo rivers passes.

"A river always has a deeper channel, which is where ships move to avoid running aground. In the Amazon River, this deeper channel was defined in 1928, and the line of the deepest channel was drawn in 1929," former Colombian Foreign Minister Julio Londoño Paredes explained to the EFE news agency.

With respect to the islands of both rivers, the Commission defined that"they will belong to the nation whose shore is closest to the island."

(See: ).

Consequently, the Amazonian islands of Zancudo number 2, Loreto, Santa Sofía, Arara, Ronda, and Leticia were assigned to Colombia, while Peru was assigned the islands of Tigre, Coto, Zancudo, Cacao, Serra, Yahuma and Chinería, the latter at the center of the current dispute.

Saint Rose of Loreto.

The Rio de Janeiro Protocol

This agreement was signed in the former Brazilian capital on May 24, 1934 to reestablish bilateral relations after the war fought by the two countries between September 1932 and May 1933, which began when"a group of Peruvian civilians and military personnel occupied the town of Leticia," explains Londoño.

This document, also calledthe 'Protocol of Peace, Friendship and Cooperation between the Republic of Colombia and the Republic of Peru', ratifies the 1922 Treaty, commits the two countries"not to wage war or to use, directly or indirectly, force as a means of solving their problems" current or future, as well as"to resolve them through direct diplomatic negotiations" or, ultimately, through international justice.

(See: ).

For this reason, the Rio de Janeiro Protocol has been invoked by both countries to justify their decisions in the current situation.

Changes in the Amazon River

The current discrepancy is due to changes in the course of the Amazon River, which since the 1970s has accumulated sediment near Leticia, the capital of the Colombian department of Amazonas, which is at risk of being cut off from its watercourse in a few years due to the emergence of new islets.

The Colombian Government considers that" the so-called 'Santa Rosa' island, along with other fluvial formations that emerged in the course of the Amazon River after the only binational assignment of islands (...) carried out in 1929, have not been assigned to either of the two Republics".

However, the Peruvian Government considers that Santa Rosa is linked to the Peruvian island of Chinería and, therefore, is subject to its sovereignty and national jurisdiction, which it has exercised for decades in total harmony with its Colombian neighbors. Leticia.

"The Law that creates the so-called District of Santa Rosa de Loreto is a unilateral act by Peru that ignores binational legal instruments, by incorporating an unassigned island...", states a statement read by Petro on Thursday at an event in Leticia.

Petro recognizes that the solution will take time and for now the Comperif will have the say, which will meet in Lima on September 11 and 12.