PHNOM PENH, Cambodia—Almost seven dozen shipping containers sitting in a Cambodian seaport that were found to be filled with plastic waste came from the United States and Canada, the Southeast Asian country’s Environment Ministry said Wednesday.

Ministry spokesman Neth Pheaktra said the total weight of the waste found in 83 containers in Sihanoukville, the country’s main port, was approximately 1,450 tonnes.

Tuesday’s discovery of the waste followed a statement at a Cabinet meeting last week by Prime Minister Hun Sen that Cambodia is not the dumping ground for any kind of waste, and does not allow the import of any kinds of plastic waste or other recyclables.

The cross-border disposal of waste became a major regional issue after China, previously its main destination, barred imports of almost all foreign plastic waste early last year. Waste shipments shifted to other countries such as Indonesia, Thailand and Malaysia, which in turn also started rejecting shipments.

Neth Pheaktra said 70 of the containers were shipped from the United States and 13 came from Canada. Both countries are major exporters of such waste.

A government committee established to look into the matter will investigate how and why the containers ended up in Cambodia, he said. He added that any company found to be involved in bringing in the waste would be fined and brought to court.

Cambodia will also begin the process of returning the waste to its countries of origin, Neth Pheaktra said.

“Cambodia is not a dustbin where foreign countries can dispose of out-of-date e-waste, and the government also opposes any import of plastic waste and lubricants to be recycled in this country,” he said.

Electronic waste, which often has toxic qualities, is also a major problem, with shipments bouncing from port to port after being turned away.

Kun Nhim, director general of Cambodia’s General Department of Customs and Excise, told The Associated Press on Wednesday that action was taken on the issue after other countries in the region such as Malaysia, Indonesia and Philippines brought the issue to the attention of Cambodian officials.

He said the 83 containers, which arrived over a period beginning in October 2018, contained only plastic waste, not toxic materials or radioactive substances.

Cambodia also has a severe problem with plastic waste it generates domestically, with little public awareness of the problem or infrastructure to deal with it.