US crude oil prices fell below $20 a barrel shortly after trading reopened on Sunday, close to the lowest level in 18 years, as traders bet production will need to shut in to cope with the collapse in demand from the coronavirus pandemic.
The US benchmark, known as West Texas Intermediate or WTI, hit a low of $19.92 a barrel, losing more than 6 per cent.
Brent, the international benchmark, lost 6 per cent to hit a low of $23.03 a barrel, the lowest since 2002.
Oil prices have fallen by more than half in the past month as widespread lockdowns in Europe and North America have slashed oil demand by a huge amount, with analysts forecasting as much as a quarter of normal global consumption could be lost.
With supplies being boosted at the same time by the price war between Saudi Arabia and Russia, traders believe the surplus could approach 25m barrels a day next month, a level that could overwhelm storage capacity worldwide within weeks.
Prices are expected to remain under pressure until the market adjusts, with producers likely to be forced to shut-in output at a scale never before seen in the modern oil industry.
WTI briefly traded below $20 a barrel earlier this month as the April contract expired, dipping violently in thin trading. But this is the first time WTI has traded sub-$20 a barrel since 2002 in normal trading conditions.