The future of the vast mineral deposits, to be mined by Rio Tinto near western Serbia's Loznica, has been a perennial political fault line in the Balkan country in recent years.

Billions of euros are at stake, with Rio Tinto saying the mine would provide thousands of jobs and secure Serbia's position in emerging energy markets.

"The government... takes measures to restore the legal order to the state that existed before the adoption of the regulation that was declared unconstitutional," the government said.

The decision follows a ruling by the constitutional court last week, saying a 2022 government move to revoke permits awarded to the Anglo-Australian mining giant was "not in line with the constitution and the law".

The mine has long pitted Serbians' festering distrust in their government against Europe's plans for a greener future, with mass protests held over the years calling for a permanent halt to the project.

Rio Tinto said the area holds one of Europe's largest reserves of lithium, a strategically valuable metal crucial for electric vehicle battery production.

- Protest leader slams government -

The deposits were discovered in 2004, but the Serbian government moved against the mining project in 2022 after weeks of protests sparked by fears over the environment and public health.

President Aleksandar Vucic has hinted that Serbia could begin mining lithium as early as 2028, following new guarantees from Rio Tinto.

"We believe that the mine would not endanger anyone or anything, but first we need to receive guarantees from Europe that the environment and the lives of ordinary citizens will be preserved and improved with new jobs and higher wages than today," Vucic said on Monday.

Rio Tinto welcomed the court decision last week. Project director Chad Blewitt told AFP the mine could become a "world-class" asset that can be developed safely according to both Serbian and EU standards.

Blewitt added the project could act as a "catalyst for the development of other industries and thousands of jobs" in Serbia now and in future.

According to Rio Tinto data, the mine in Jadar could produce 58,000 tonnes of lithium annually, enough for 1.1 million electric vehicles.

Following Tuesday's announcement, Savo Manojlovic -- a leading organiser of the protests against the mine -- slammed the decision.

"The government will be responsible for any unrest and conflict in society, as it has trampled on the country's constitution, occupied its institutions, and turned into a puppet of foreign interest," Manojlovic wrote on social media.