European Union governments should prepare for a prolonged disruption to energy markets as a result of the Iran war, the bloc’s energy chief has told ministers ahead of an emergency meeting on Tuesday, according to Reuters.

In a letter to energy ministers, dated March 30 and seen by Reuters, EU Energy Commissioner Dan Jorgensen said governments were “encouraged to make timely preparations in anticipation of a potentially prolonged disruption”.

European gas prices have risen more than 70% since the U.S.-Israeli war with Iran began on February 28.

The bloc’s supplies of crude oil and natural gas have not been hit directly by the closure of the Strait of Hormuz, since Europe imports most of those energy sources from suppliers outside of the Middle East, according to the report.

Jorgensen said Brussels was particularly concerned in the short term about Europe’s supply of refined petroleum products such as jet fuel and diesel.

Jorgensen recommended in his letter that governments avoid measures that would limit trade of petroleum products or discourage output at European refineries.

“Member States are ⁠encouraged to defer any non-emergency refinery maintenance,” he said.

EU energy ministers will hold a video call on Tuesday afternoon to coordinate their response to the disruption triggered by the Iran war.