Sudan declared an economic state of emergency on Thursday after its currency fell sharply in recent weeks, setting up special courts to prosecute what officials called a "systematic operation" to vandalise the economy.

The transitional government, in charge of the country since the ouster of Omar al-Bashir last year, will criminalise purchasing, selling, possessing or smuggling of raw gold or precious minerals, key hard-currency earners.

The pound has declined in recent weeks on what officials blamed on manipulation by those opposing the transitional government.

"We are able to simply say what happened is an open war against the revolution, the economy, the government," Information Minister Faisal Saleh told a news conference.

Special courts will be set up in coming days to fight smuggling and other illicit activities.

Sudan, a gold producer, took steps in June to further open up the precious metals trade to private investors, allowing them to handle all exports and taking the business out of state hands.

But authorities recently noted people selling gold at above market price to intentionally move the exchange rate.

"What is happening is a systematic operation to vandalise the Sudanese economy, choke the transitional government, and we will not relent or be complacent," acting Finance Minister Hiba Mohammed Ali said.

Bashir's government had tried to crack down on the black-market traders by arresting some of them, but had little success. The currency has been devalued four times since 2018.

Inflation in Sudan is second only to that of Venezuela, with the headline rate climbing to 143.78 percent in July.

Security forces would also step up border controls to stop the smuggling of commodities, officials said.

Justice Minister Nasredeen Abdelbari said Sudan expected to be removed "soon" from a US list of state sponsors of terrorism going back to Bashir's Islamist government.

The designation makes Sudan technically ineligible for debt relief and financing from the International Monetary Fund and World Bank. The US Congress must approve any removal.