For the first time since the Ukraine war, oil prices fell below $ 100 per barrel.
Brent futures were down $8.9, or 8.3%, to $98 a barrel at 1125 GMT, while US West Texas Intermediate (WTI) crude was down $8.97, or 8.7%, to $94.04 a barrel.
Both benchmarks fell below $100 a barrel for the first time since March 1.
Brent has lost almost $40 since 14-year highs reached on March 7, while WTI has fallen by over $30 since touching highs since 2008 almost a week ago.
Russian foreign minister Sergi Lavrov on Tuesday that Moscow is in favor of the 2015 Iran nuclear deal resuming as soon as possible and is waiting for Washington to lift sanctions on Tehran.
Talks between Ukrainian and Russian negotiators to ease the crisis were expected to continue on Tuesday.
In addition, the US Federal Reserve’s Federal Open Market Committee (FOMC) starts a two-day meeting on interest rates on Tuesday, at which the market expects the first US interest rate increase for four years.