The European Commission will instruct governments to be flexible in enforcing EU rules on gas imports, diplomats said on Thursday, amid fears they could hold up liquefied natural gas (LNG) deliveries needed to stabilize supplies during the Iran crisis.

The Commission plans to issue guidance before March 18 on how to apply rules within the European Union's law to phase out Russian gas, the diplomats said.

The guidance marks an attempt by Brussels to prevent its Russia phaseout rules from inadvertently choking Europe's gas supply at a moment of vulnerability. It would not affect the EU's phase-out of Russian gas.

With the Iran conflict rattling global LNG flows and raising the risk of cargo diversions, EU officials fear rigid enforcement could delay or strand shipments, undermining the bloc's ability to keep storage adequately stocked and safeguard energy security heading into next winter.

The rules in question require that shipments of LNG from certain non-Russian countries receive "prior authorization" - meaning companies must provide European customs authorities with proof of the gas's origin five days before it arrives in the EU.

The main country affected by a softening of the "prior authorization" rules would be Azerbaijan, which last year supplied 4% of EU gas imports.

The EU has already said its main gas suppliers, including Norway and the U.S., will not face the prior authorization rules since the EU deems the risk of Russian gas entering their exports to be low.

Europe's gas industry had already asked Brussels to temporarily suspend the rules on prior authorization.

"We simply cannot afford that a single flexible LNG cargo is delayed in port, stranded at sea, or rerouted to Asia because prior authorization is unclear or pending," industry group Eurogas said in a statement on Thursday.