Swiss authorities acting on a US request have seized three valuable paintings linked to an investigation into scandal-hit Malaysian state fund 1MDB, they said today.

A spokesperson for the Federal Office of Justice said the paintings ordered seized were van Gogh's La maison de Vincent à Arles and Monet's Saint-Georges Majeur and Nympheas avec Reflets de Hautes Herbes.

She was confirming a report by the Neue Luzerner Zeitung newspaper.

"The operation is not over yet so we will not comment at the moment on the location of the paintings," she said.

The US government yesterday filed lawsuits seeking to seize US$1 billion in assets bought with money believed to have been stolen from 1MDB.

Meanwhile, Swiss bank UBS said it was working with authorities investigating banks' ties to scandal-hit 1MDB and that it had reported some deals which it had concerns.

"In this case, UBS self-reported the suspicious transactions and is working closely with regulators to address this matter," it said in a statement.

The Monetary Authority of Singapore earlier said it had completed inspections of DBS, Standard Chartered and UBS and that preliminary findings had shown instances of "control failings" in all three banks and "weaknesses in the processes for accepting clients and monitoring transactions".

- Reuters