(Reuters) – The Moscow Exchange will ban the use of dollars as collateral to underwrite transactions, it said on Monday, as Russia seeks to cut dependence on currencies of nations that have imposed sanctions on it.

A statement posted on the exchange’s website said the new policy would come into effect on Aug. 29. It gave no details.

Earlier this month the exchange – the country’s largest bourse – said it would limit the use of dollars as collateral to 25% from 50%.

Russian authorities have voiced concerns about individual and corporate holdings of currencies that it terms “unfriendly”, calling for their conversion into alternatives.

The United States and its allies have imposed several rounds of sanctions, including those targeting the country’s largest lenders and Putin, since Russian forces invaded Ukraine in February.

(Reporting by David Ljunggren; Editing by Jan Harvey)