Saudi Arabia's de facto ruler is using the oil-rich kingdom's sovereign wealth fund to bankroll vanity projects linked to a host of rights abuses, Human Rights Watch said on Wednesday.

A 93-page report from the New York-based group describes how Crown Prince Mohammed bin Salman has asserted control over the kingdom's Public Investment Fund (PIF), which now manages assets worth around $925 billion compared with $84 billion a decade ago.

It accuses the 39-year-old crown prince of seizing companies and assets from elite Saudis rounded up during high-profile anti-corruption operations beginning in 2017, the same year he became first in line to succeed his father, King Salman.