North Sea oil fell 6 percent from the previous day and was trading at around $98 per barrel in futures trading for May at about 2 a.m. Swedish time.
U.S. WTI also fell sharply, to $87.50 a barrel, down from just over $91 a barrel the day before.
The oil price was around $70 per barrel before the U.S. and Israel's attack on Iran at the end of February and has since gone above $100 per barrel several times.
The price drop comes after news that Iran has received a basis for a peace agreement from the United States and has opened up to allowing "non-hostile" ships through the Strait of Hormuz.
