Portuguese Prime Minister António Costa abruptly resigned on Tuesday, hours after police raided his residence, government ministries, and other properties as part of a major corruption probe.

Mr Costa said in a brief televised address that he handed in his resignation to President Marcelo Rebelo de Sousa. The socialist politician said his conscience was clear, but the allegations were too serious for him to continue holding office.

The investigation revolves around suspicions of bribery and favouritism in the allocation of concessions for lithium mining in the Montalegre area and the production of green hydrogen near the southern town of Sines, the state news agency Lusa, the state broadcaster RTP, and other Portuguese media reported

Five people were reportedly detained, including Mr Costa’s cabinet chief, Vítor Escaría.

Entrepreneur Diogo Lacerda and the mayor of Sines, Nuno Mascarenhas, as well as two other businessmen, were also taken into custody, RTP and Lusa said.

It was not initially known what exactly each was accused of.

The prosecutor’s office confirmed that searches had been conducted at dozens of residences and offices, including the ministries of infrastructure and environment, as well as Mr Costa’s residence.

But neither the prosecutors nor the police have provided further details.

The shock of the resignation came after opposition parties demanded Mr Costa, 62, step down and new elections be held. He has been prime minister since 2015.

The region of Montalegre in the far north of Portugal is believed to have the largest lithium deposits in Europe, set to be mined despite strong opposition from residents.

The metal is crucial for battery production.

A decommissioned coal-fired power facility in Sines, near the capital, Lisbon, ceased operations in 2021, but it is now positioned to produce green hydrogen by harnessing sustainable energy sources.

Both projects are seen as essential components of Portugal’s transition away from the use of fossil fuels.

(dpa/NAN)