UPDATE 2-UBS Belgium boss charged in tax fraud investigation

* Charges include organised crime and money laundering

* Alleged fraud amounted to several billion euros

* UBS says cooperating with Belgian authorities (Updates with CEO charged and released)

BRUSSELS, June 19 A Belgian judge charged the head of UBS Belgium on Thursday with involvement in an alleged multi-billion euro tax fraud by the Swiss bank's Belgian unit.

Belgian police carried out raids on Thursday morning at the bank and at the homes of a client and of UBS Belgium chief executive Marcel Bruehwiler, Brussels prosecutors said.

Bruehwiler was then questioned by a judge for several hours.

"The investigating judge charged him with organised crime, money laundering, illegal exercise of a job as a financial intermediary in Belgium and serious and organised fiscal fraud," the prosecutors said in a statement.

Bruehwiler denied all charges, prosecutors said.

The judge decided not to hold him in detention.

When the investigation concludes, a court will need to rule on whether there is sufficient evidence to proceed with the charges against Bruehwiler.

Prosecutors said the alleged criminal activity began about 10 years ago with Belgian clients who were looking for ways to limit tax payments. The bank, they said, probably enabled them to evade tax fraudulently.

Information had come from compliance officers who had either left or been fired by UBS Belgium, prosecutors said.

"These people could no longer tolerate the fraudulent practices, which they brought to light," prosecutors said.

UBS said it is fully cooperating with the Belgian authorities and does not tolerate any activities intended to help its clients circumvent their tax obligations.

Brussels prosecutors said this month that they had launched an investigation into UBS Belgium for suspected money laundering and organised crime.

The Swiss bank offers wealth management services in Belgium with offices in Brussels, Antwerp and Ghent. (Reporting by Robert-Jan Bartunek; Writing by Philip Blenkinsop; Editing by Louise Ireland)