Switzerland's FINMA financial watchdog suspects banks being probed about ties to scandal-hit Malaysian state fund 1MDB had lax money-laundering controls, it said on Thursday, but declined to give any details about four open investigations.
"FINMA has indications here that the measures for combating money laundering were insufficient," a spokesman said.
He was responding to news that the Monetary Authority of Singapore had completed inspections of DBS, Standard Chartered and UBS.
Preliminary findings there showed instances of "control failings" in all three banks and "weaknesses in the processes for accepting clients and monitoring transactions".
UBS had no immediate comment.
FINMA in May found Swiss private bank BSI in breach of money laundering regulations in connection with 1MDB. BSI has filed an appeal against that finding.