BRUSSELS — The European Commission is asking member countries to consider cutting back on oil and gas use, especially in the transport sector, in preparation for “prolonged disruption” to energy supplies from the Iran war.

The request, made by EU energy chief Dan Jørgensen, reflects fears that the conflict in the Persian Gulf is graduating from a price problem to an all-out energy supply crisis, with serious implications for the global economy.

In a letter to national energy ministers, seen by POLITICO, Jørgensen said that national governments should consider “voluntary demand saving measures … with particular attention to the transport sector.”

That could mean governments asking citizens to drive or fly less to save fuel for more essential purposes, as is already happening in some Asian countries.

European energy ministers will hold an emergency meeting Tuesday to discuss how to address the energy crisis.

In his letter, Jørgensen said Europe’s transport sector faces rising costs and supply shortages due to the industry’s heavy reliance on the Persian Gulf, which the EU relied on for over 40 percent of its jet fuel and diesel imports.

He added that the growing shortage is compounded by the “limited availability of alternative suppliers and of refining capacity for specific products within the EU.”

“Member States should refrain from taking measures that may increase fuel consumption, limit the free flow of petroleum products or disincentivize EU refinery output,” Jørgensen said. He added that countries should consider the cross-border impact of national measures to preserve “EU-wide coherence.”

For now, European countries have yet to invoke demand-saving measures, which were a staple of the 1970s oil crises, which saw governments impose gasoline rationing and “drive-free” Sundays. The International Energy Agency has already laid out a list of proposals for demand reduction this time around, including encouraging homeworking and lowering highway speed limits.

The letter comes amid waning confidence that the war in Iran will be over quickly, making long-term shortages more likely. EU countries should make “timely preparation in anticipation of a potentially prolonged disruption,” Jørgensen said.

The senior energy official also recommended that countries boost monitoring and information-sharing, “defer non essential refinery maintenance” and consider increasing the adoption of biofuels to replace fossil fuel products.