Guatemala made a "historic" cocaine bust this month, assisted by US authorities.

The bust doubled the total amount of cocaine that Guatemala has intercepted so far this year.

Guatemala has made progress against drug trafficking, but corruption and weak governance allow the trade to remain robust.

Guatemalan marines and the US Coast Guard have made a "historic" bust of cocaine, intercepting at least three tons of the drug on a ship 300 nautical miles off the Central American country's coast in international waters.

The Guatemalan army said the vessel, a Tanzanian-flagged cargo ship called Tiamat, arrived at Puerto Quetzal on Guatemala's Pacific coast on Monday, several days after it was stopped. Guatemala's navy reported detaining 13 people, among them citizens of Colombia, Ecuador, and Peru.

Guatemala's Defense Ministry said Guatemalan marines and US Coast Guard personnel made the discovery while inspecting the ship, finding the drugs hidden in compartments with false bottoms. The quantity seized was "the biggest in the history of Guatemala in the fight against narcotrafficking," the ministry said.

Military spokesman Oscar Perez confirmed that the substance in question was cocaine and said that the US authorities who detected the illicit shipment were carrying out the search of the vessel with the assistance of local authorities and would be the ones to take custody of the drugs.

Guatemalan military vehicles in front of the cargo ship Tiamat, intercepted while carrying cocaine, at Puerto Quetzal in early May 2018. Guatemalan news agency

Guatemala's interior minister, Enrique Degenhart, told reporters that the seizure was the result of more than 15 days of planning done in collaboration with US anti-narcotics authorities.

Prior to this bust, Guatemalan security forces had seized more than three metric tons of cocaine already, and this seizure brings the total to more than six metric tons. It comes after a record-setting year for seizures in 2017, when authorities intercepted 13.6 metric tons, topping the 12.8 metric tons captured in 2016. (The US State Department recorded higher amounts for both years.)

Guatemala, like neighboring El Salvador and Honduras, is a nexus for the international drug trade, with drugs often arriving from South America by boat and heading overland to Mexico and toward the US — movement facilitated by corruption and limited government capacity.

Guatemalan police carry packages of cocaine seized in Puerto Quetzal, at the air force base in Guatemala City, June 13, 2014. REUTERS/Jorge Dan Lopez

Homegrown and foreign traffickers, like Mexico's Zetas and Sinaloa cartels, have been active in Guatemala, but it has made progress against crime, avoiding the high rates of violence seen by its neighbors. It recorded a historic reduction in homicides during the first four months of 2018.

But with a long Pacific coastline and a porous border with Mexico, Guatemala has seen increases in cocaine smuggling by both sea and air in recent years, according to the US State Department.

Cocaine seizures in 2016 hit a 10-year high, Guatemalan authorities said in early 2017.

In March this year, during a visit by US ambassador to the United Nations Nikki Haley, Guatemalan security officials requested more equipment and training from the US to combat drug trafficking.

Officials said at the time that they knew Trump's comments criticizing countries in the region for what he perceived as failing to confront the drug trade were not directed at Guatemala — one of the few countries to support Trump's decision to move the US embassy in Israel to Jerusalem and plans to move its own embassy there as well.

But they stressed that their security forces did not have adequate resources to keep up with drug traffickers, often struggling to detect stealthy semi-submersible vessels or running out of fuel while trying to catch smugglers.