September natural gas futures at the Netherlands-based TTF began the trading day in the European market at around €56 per megawatt-hour.
The contracts climbed as high as €60.5 during the day before reaching €59.5 per megawatt-hour at 17:10 TRT. Having closed the previous trading day at €55.5, the contracts therefore rose 8%.
Uncertainty over shipments through Hormuz
Uncertainty over shipments through the Strait of Hormuz was among the factors behind the rise in European natural gas prices.
Ismail Baghaei, spokesperson for Iran's Foreign Ministry, said the Strait of Hormuz would not be a safe passage route if the United States continued its current policy and naval blockade.
Hot weather and low inventories
The heat wave expected to affect Europe again this week is forecast to increase electricity demand. Natural gas storage facilities across the continent being at historically low levels is also intensifying upward pressure on prices.