US crude oil futures tumbled on Monday
US crude oil futures tumbled on Monday on late liquidations ahead of front-month February contract's expiration at the end of the session.
February crude on the New York Mercantile Exchange was down $1.08 at $50.91 per barrel after dropping as low as $50.80.
The more actively traded NYMEX March crude contract was down $1.25 at $52.15, trading $US52.10 to $54.65.
In London, ICE March Brent crude fell back $1.06 or two per cent to $52.38 a barrel after trading from $52.18 to $54.60.