BUENOS AIRES, Argentina (AP) — Several former top military officials in Paraguay have been arrested as part of a cross-border law enforcement operation with Brazil to disband an arms smuggling ring that brought firearms from Europe to South America, officials said Tuesday.

The U.S. Department of Homeland Security was also involved in the year-long investigation, according to Paraguay authorities.

“The weapons were imported from Europe to Paraguay, where they were defaced and resold to intermediary groups operating on the Brazil-Paraguay border, ultimately reaching major criminal factions in Brazil,” Brazilian federal police said in a statement.

Close to 43,000 pieces of such weapons — worth around $243 million — were imported to Paraguay over the past three years under the scheme, Brazilian authorities said.

At least 13 people have been detained in Paraguay, including the former head of Paraguay’s office in charge of controlling the imports and distribution of firearms known as Dimabel, which is a division of the armed forces. The former chief of Paraguay’s Air Force, Gen. Arturo González, was also detained.

The arrests were part of at least 20 raids that took place in Paraguay and 20 in Brazil. One raid was also carried out in Kansas, according to Paraguayan authorities.

The investigation was able to determine that the military officials were involved in authorizing “the importation of weapons, altering documents to conform to firearms laws, as well as authorizations for irregular sales in exchange for significant sums of money,” according to a statement by Paraguay’s National Anti-Drug Secretariat.

A company based in Paraguay’s capital of Asunción that is led by an Argentine businessman was importing the weapons from manufacturers in Croatia, Turkey, the Czech Republic and Slovenia. The company allegedly used its contacts in Dimabel to get quick approval for the imports.

Once in South America, the weapons were sold to intermediaries with connections to criminal gangs in Brazil. Money from the operations was allegedly laundered through the United States.