Deposits at Saudi American Bank (Samba) fell by almost $600m (£410m) in the first three months of the year.

The fall could be in protest against the Bush administration's ban on US banks accepting transactions from some Islamic charities believed to have connections with terrorism, according to the Financial Times.

Samba is 22.8% owned by the US' Citibank, and is Saudi Arabia's second largest bank with 57 branches and 2,236 employees.

Boycott

Dwindling deposits is unusual at the bank which enjoyed steady gains during each quarter last year.

Some Saudi investors are thought to be moving their money to other banks as part of a wider boycott of US products in protest at the superpower's perceived bias towards Israel and against Arabs.

Samba chief executive, Mike de Graffenried, refused to comment on the reason for the decline, and some analysts acknowledged that there could be other reasons for the drop.

The revelation of falling deposits came as the bank announced a rise of 4% in quarterly profits to 549m Saudi riyals (£100.5m; $146.4m).