Oil prices fell sharply today, with U.S. crude briefly dropping below $20 and Brent hitting its lowest level in 18 years, on heightened fears that the global coronavirus shutdown could last months and demand for fuel could decline further.

Brent crude, the international benchmark for oil prices, was down $2.09, or 8.4%, at $22.84 by 09:17 GMT, after earlier dropping to $22.58, the lowest since November 2002.

U.S. West Texas Intermediate (WTI) crude fell $1.11, or 5.2%, to $20.40. Earlier in the session, WTI fell as low as $19.92.

“Global oil demand is evaporating on the back of COVID-19-related travel restrictions and social distancing measures,” said UBS oil analyst Giovanni Staunovo.

The price of oil is now so low that it is becoming unprofitable for many oil firms to remain active, analysts said, and higher cost producers will have no choice but to shut production, especially since storage capacities are almost full.