Australia has overnight imposed an immediate ban on Australian exports of alumina and aluminium ores including bauxite to Russia.

Russia currently relies on Australia for nearly 20% of its alumina needs, according to a statement from the office of the prime minister of Australia, Scott Morrison.

The move is designed to limit Russia’s capacity to produce aluminium — a critical export for the country, the government said.

“Aluminium is a global input across the auto, aerospace, packaging, machinery and construction sectors, and a critical input into armaments industries,” said Morrison.

Australia’s foreign minister Marise Payne has imposed the export ban under the countries’ autonomous sanctions against Russia.

The government said it would “work closely” with exporters and peak bodies that will be affected by the ban to find new and expand existing markets.

“This significant step demonstrates the Morrison Government’s absolute commitment to holding the Putin regime to account for the egregious way in which it is flouting international law and the law of armed conflict by invading its neighbour without justification, and targeting innocent civilians,” Australia said.

Anglo-Australian mining giant Rio Tinto owns an 80% stake in Queensland Alumina Ltd (QAL) in a joint venture with Russia’s Rusal International PJSC, the world’s second-largest aluminium producer.

Australia recently imposed sanctions on two Russian businessmen with links to its mining industry, one of them being billionaire Oleg Deripaska who holds stakes in QAL.

Separately, Australia said it will support Ukraine’s energy security by donating at least 70,000 tonnes of thermal coal following a request for assistance from Ukraine, supported by Poland, and discussions with other European partners.

“The assistance will help keep the country’s coal-fired power generators operating and supplying electricity to country’s power grid, supporting the Ukrainian people by keeping lights on, homes heated, and factories running at this very difficult time,” the Australian government said.

Whitehaven Coal has quickly arranged a shipment, and the Government is now working with Whitehaven and the Ukrainian and Polish Governments to deliver the supplies at the earliest available opportunity.

The cost of the coal and its delivery to the destination port will be met by the Australian Government.

“In a very tight supply market, we have been able to commit this important shipment while ensuring contracted customer demand is met,” Whitehaven said in a statement.

“We will work closely with the Australian Government and one of its key supply chain partners, Trafigura, to ensure the prompt delivery of the cargo.”