UBS is under investigation in Singapore along with other banks for possible manipulation of Libor and other benchmark rates, the Swiss bank said on Tuesday.

In notes to its third quarter earnings report, UBS said that the Monetary Authority of Singapore (MAS), as well as authorities in the United Kingdom, United States and Switzerland, are conducting investigations into whether it and other banks tried to manipulate rates.

More than a dozen banks are under investigation by regulators in the United States, Europe and Asia. However, this is the first time that UBS has disclosed that it is involved in the probe in Singapore.

"These investigations focus on whether there were improper attempts by UBS (among others), either acting on our own or together with others, to manipulate LIBOR and other benchmark rates at certain times," it said.

The MAS ordered members of the Association of Banks in Singapore in July to review how they set their benchmark interbank lending rates, focusing on the Singapore interbank offer rate (Sibor) and the Swap Offer Rate (SOR).

That probe was extended in late September when the regulator said banks must also look at how rates for non-deliverable foreign exchange forwards are set.

It ordered banks to report any irregularities they uncovered and to take disciplinary action against any staff involved.

An MAS spokesman referred to the statement from last month that said that the bank reviews were still at a preliminary stage.

UBS was the first bank globally to report suspected rate rigging, and has received conditional immunity from some authorities for cooperating in their probes. (Reporting by Rachel Armstrong and Kevin Lim; Editing by Michael Urquhart)