Police in Brazil have seized 444 containers in an investigation into illegal logging in the country’s vast Amazon, federal authorities said on Thursday, as the nation seeks to cut down on the widespread practice.

The seizures are part of an investigation taking place at ports in the Brazilian riverside city of Manaus, a key trans-shipment point for illegal timber, police said in a statement.

Police have inspected only one-fifth of the containers so far. They were found to contain logs that, if laid in a line, would stretch for 1,500 kilometers (930 miles), the police said.

About half of the logs were bound for export to the United States or Europe, they added.

The Amazon, most of which is located in Brazil, is the world’s largest tropical rainforest and soaks up vast amounts of carbon dioxide.

Brazil’s efforts to protect the forest, which experts say is important to curbing global warming, have been mixed in recent years. In October, the country’s environment ministry said that overall Amazon deforestation fell 16 percent for the year through July 2017. However, that was the first drop in three years.