The UAE has instructed its banks and finance companies to provide information on the accounts of 19 Saudi citizens detained by Crown Prince Mohammed Bin Salman in a sweeping "anti-corruption" campaign.
Unnamed banking sources told Reuters that they believe the UAE authorities were acting at the request of the Saudis.
The sources said that the request was contained in a circular sent earlier this week and banks have responded, adding that the banks had not been asked to freeze the accounts.
Saudi Arabian banks have already frozen more than 1,700 accounts belonging to individuals and companies in the Kingdom.
The most prominent of those held against their will in the Ritz-Carlton Hotel in Riyadh include the Kingdom's best-known international investor, Al-Waleed Bin Talal who is thought to be worth $16.7 billion, according to Forbes magazine.
Business analysts say that the anti-corruption crackdown may see the government seize up to $800 billion in cash and assets at a time when the Saudi treasury is struggling to fund its giant economic projects.
While Saudi Arabia has mutual legal assistance arrangements with other Gulf Arab countries that help it seek such information in criminal cases, the nature of the crime committee by detained Saudi citizens remains unclear.
Critics believe that the "anti-corruption" drive is further proof that Bin Salman is eradicating any opposition, ensuring his succession and gaining overall control of the country.