The Belarusian president, Alexander Lukashenko, has signed a new law granting him lifelong immunity from criminal prosecution and preventing opposition leaders living in exile from running in future presidential elections, writes The Guardian.

The law theoretically applies to any former president and members of his or her family. In reality, it is only relevant to the 69-year-old Lukashenko, who has ruled Belarus with an iron fist for almost 30 years.

The new measure appears aimed at further shoring up Lukashenko’s power and eliminating potential challengers in the country’s next presidential election, which is due to take place in 2025.

The law significantly tightens requirements for presidential candidates and makes it impossible to elect opposition leaders who have fled to neighbouring countries in recent years. Only citizens of Belarus who have permanently resided in the country for at least 20 years and have never had a residence permit in another country are eligible to run.