Belgian investigators are questioning the head of UBS AG’s local arm today as part of a multibillion-euro tax fraud probe, prosecutors said.

Police today searched the home of Marcel Bruehwiler and a client as well as the bank’s offices, officials said in an e- mailed statement.

Information pointing to “serious organized fiscal fraud” was “obtained via very specific accusations of compliance officers who have either left the bank, or been laid off and could no longer stand the modus operandi of UBS,” prosecutors said. The tax evasion is “estimated at several billion euros.”

UBS employees approached wealthy Belgian taxpayers including chief executive officers and athletes over a decade, encouraging them to open undeclared accounts in Switzerland, M... Belgique magazine reported last month, without saying where it got the information. UBS Belgium, the bank’s local arm, helped to organize the transfer of large amounts of client money to Switzerland, the magazine said.

“We conduct our business in full compliance with applicable law and regulations,” UBS spokesman Yves Kaufmann said in a phone interview today. “UBS does not tolerate any activities intended to help its clients circumvent their tax obligations. We fully collaborate with the Belgian authorities.”

UBS Belgium’s office in Brussels couldn’t provide contact details for Bruehwiler’s representatives or lawyer.

U.S. Probe

The Belgian probe is the latest in a series of tax-evasion cases involving the Swiss lender. UBS avoided U.S. prosecution in 2009 by admitting it aided tax evasion, paying $780 million and handing over data on 250 accounts. It later disclosed information on about 4,450 more accounts.

Paris prosecutors are also investigating allegations UBS’s French unit helped clients hide their wealth in Swiss accounts. The French banking regulator fined the lender 10 million euros ($13.6 million) last year for deficient controls against tax fraud and illegal sales practices. Tax investigators searched its offices in Paris, Lyon and Strasbourg in 2012.

Switzerland’s Credit Suisse Group AG paid $2.6 billion in fines after its bank unit pleaded guilty to helping Americans cheat on their taxes. U.S. authorities are seeking more than $10 billion from France’s BNP Paribas SA for alleged breaches of sanctions on countries including Iran and Sudan a person familiar with the matter has said.