The oil stockpiles that cushion the world from supply shocks have become “scarily thin,” putting markets at risk of worsening unless the Strait of Hormuz reopens, according to the head of Saudi Arabia’s state producer.

He was speaking just days after governments in the world’s biggest economies announced plans to release as much as 100 million barrels of emergency oil and diesel stocks to ease rising fuel costs.

“Until Hormuz fully re-opens and confidence returns, the crude reality is that pressure at both ends of the barrel will intensify,” Amin Nasser, chief executive of Saudi Aramco, said at the Energy Intelligence Forum in London on Monday. “While the squeeze on crude is serious, refined fuel prices have risen even more sharply.”Releasing stockpiles will buy economies some time but won’t fix the imbalances between supply and demand, Nasser said. Even after the vital shipping chokepoint at Hormuz reopens, it may take as long as two years for energy-consuming countries to replenish their stockpiles, he said.

Gulf producers are working to ramp up production and exports and have succeeded in boosting crude flows to near pre-war levels. Saudi Arabia and neighbors like the United Arab Emirates and Kuwait have been using their own tankers to ship crude through Hormuz, which has been at least partly obstructed since the US and Israel attacked Iran at the end of February, kicking off a regional war.

The higher flows have provided scant relief for oil markets, which are still pricing in security risks to supply in the Persian Gulf and Red Sea. Brent crude, the international benchmark, has traded around $100 a barrel over the past month, even as more tankers transited Hormuz.

Saudi Arabia has been a key part of that increase as Aramco over the past month boosted crude shipments from its main export terminal at Ras Tanura in the Persian Gulf. The company reacted quickly to a temporary halt to its main cross-country pipeline after an attack last month.

The company has since brought flows on the East-West pipeline back to about 80% of capacity, meaning it also has more oil to ship from the Red Sea.

Aramco’s oil supplies have proved resilient through the conflict by relying on international storage and working to quickly repair damaged infrastructure, Nasser said. He didn’t mention reports of recent attacks on the kingdom in his speech.

Aramco is looking for alternative crude export routes and additional international storage facilities to avoid relying too much on any single method of reaching global buyers, he said.