Belgrade (AFP) – Serbian prosecutors indicted the country's culture minister and three others on Monday over "alleged illegalities" in the approval process of a hotel project linked to US President Donald Trump's son-in-law Jared Kushner.

Plans to transform the bombed-out former Yugoslav army headquarters in Belgrade into a high-rise hotel first stalled in May when allegations emerged that the move to revoke the building's protected status had been based on a forged document.

In a statement, organised crime prosecutors said they had indicted Culture Minister Nikola Selakovic and three others over alleged abuse of office and forgery of an official document that had allowed the removal of the site's "cultural-heritage status".

Despite an ongoing investigation, lawmakers moved to fast-track the development last month, claiming it was an urgent project.

Protests erupted afterwards in the capital, with demonstrators calling for the towering ruins to be preserved both for their unique modernist architecture and as a memorial to mark the 1999 NATO bombing that left the building damaged.

Affinity Partners, a Miami-based investment firm linked to Kushner, signed a 99-year land deal with the Serbian government last year to redevelop the site shortly after its cultural asset status was revoked.

But prosecutors said in May that the acting head of the Institute for the Protection of Cultural Monuments, Goran Vasic, had admitted to forging an official document.

Vasic was one of the four indicted on Wednesday, alongside Selakovic and two other officials.

If found guilty, they could face up to five years in prison.

President Aleksandar Vucic, who has hosted Kushner several times, has publicly backed the project and previously said he would pardon anyone who faced charges over the development.

"I will not give them the opportunity to prosecute those who are not guilty of anything. I am guilty. I am the one who wanted Serbia's modernisation. I am the one who wanted to bring in a major investor," Vucic said on Monday during a visit to the southern city of Nis.