For most of the past six years, the leaders of Russia and Saudi Arabia have worked together to control the global oil market during times of war, pandemic and dizzying price swings.

But their alliance appears strained in ways that could help the Biden administration, which has been eager to stave off another sharp spike in energy prices ahead of Secretary of State Antony J. Blinken’s visit to Saudi Arabia this week.

At last weekend’s OPEC Plus meeting, the oil cartel, led by two countries, Saudi Arabia and Russia, quietly broke up. Saudi Arabia has said it will cut its exports by a million barrels of oil a day in an effort to support falling prices. But Russia has made no new commitment to cut its exports.

It was the second time the partners had recently diverged on oil policy. Just two months earlier, Russia and Saudi Arabia, which together sell more than 20 percent of the oil used in the world, agreed to cut production. But while Saudi Arabia followed suit and sold less oil to other countries, Russia does not appear to have done so. Russia recently stopped disclosing information about its oil industry, but analysts estimate that Moscow has increased exports, undermining an earlier agreement.

The Saudi-Russian oil alliance has always been about the common goal of supporting oil prices and maximizing export earnings. But Russia’s war in Ukraine changed the dynamics of the relationship. Russia is increasingly willing to accept lower prices to sell more oil, with much of it going to China and India, as it needs money to finance its war effort.

Russia’s pressing needs – along with weak global demand for oil – have helped push prices down. That has helped lower energy prices around the world, including in the United States, where President Biden has made lowering gasoline prices a top policy goal after the war in Ukraine began last year.

As of Wednesday afternoon, the benchmark U.S. crude price was just under $73 a barrel, about the level before the weekend OPEC Plus meeting and down from $120 last summer.

“The goals of Russia and the cartel diverge,” said Mikhail Krutikhin, a veteran Russian oil expert now based in Oslo. “There is no trust in Russian data and there is no trust in Russian actions.”

Saudi officials have not publicly criticized Moscow, appearing to back President Vladimir V. Putin out of a corner in an effort to preserve a partnership that began in 2016 and has generally been mutually beneficial.

Bruce Riedel, a former Middle East analyst with the Central Intelligence Agency, disagreed with the idea that Saudi-Russian relations are strained. He said that by unilaterally limiting oil production, Saudi Arabia is distancing itself from the United States and specifically from the Biden administration.

“The Saudis have definitely sided with Russia by cutting oil production to raise prices,” said Mr. Riedel, now at the Brookings Institution. “The timing on the eve of Blinken’s visit was added to the message.

While the Saudi move to cut production and raise global prices is problematic for Washington, Riyadh appears to be hedging between its long-time ally, the United States, and Russia, its newer partner in oil politics.

Both the Saudis and the United States have reasons to stabilize their relationship, said Robert Jordan, a former US ambassador to Saudi Arabia.

“The Saudis want an American fighter jet, nuclear technology and security guarantees,” Jordan said. “The US wants it. recognize Israel and keep oil production flowing.”

Relations with Saudi Arabia have helped Russia during its all-out war with Ukraine. While Western countries began withdrawing investments from Russia last year, Saudi Arabia’s Kingdom Holding Company invested hundreds of millions of dollars in Russian energy companies. After that, Saudi Arabia increased imports of Russian fuel oil for its power plants, while other countries reduced or ended purchases of Russian energy.

In September, the two countries led OPEC Plus to cut oil production, to the dismay of the Biden administration. The move was seen as a rebuke to Mr Biden, who traveled to Saudi Arabia in July and traded blows with Crown Prince Mohammed bin Salman – after criticizing him during his presidential campaign. The president, chastised by Republicans for soaring inflation, hoped the Saudis would increase oil production or at least not cut it.

However, the Russian-Saudi oil partnership has often been unstable. In 2020, as the Covid pandemic undermined the global economy and oil prices, Russia refused to cooperate with Saudi officials on deep production cuts to stabilize prices. In response, Saudi Arabia flooded the market with oil, driving down the price of oil and severely damaging Russian oil companies.

In a recent television interview, Prince Abdulaziz bin Salman, the Saudi energy minister and half-brother of Prince Mohammed, recalled the brief split with grandeur. “It wasn’t a question of price, profit or income,” he said. “It was a question of ‘to be or not to be’: Who rules this sector?”

Still, the alliance has endured, and energy experts predict it will continue even as various OPEC Plus members show increasing independence.

“I see tensions emerging, but it’s still an alliance because they still need each other,” said Bill Richardson, a former US energy secretary and ambassador to the United Nations.

While the group of producers extended collective supply cuts, the United Arab Emirates could increase its production quota for next year. In the final tally, OPEC Plus’ latest decision could cut global oil supplies by a modest one million barrels a day for at least a month from a global market of just over 100 million barrels a day, according to oil analysts.

The two countries still have a lot in common, including how they view some American policies. When the United States and European countries imposed a price cap on Russian oil exports last year, Saudi Arabia and other energy-producing countries in the Middle East saw the action as a potential threat, a policy that could be used to cut into their profits in the future.

“It would make no sense for the two countries to walk away from this key alliance at a time when energy security around the world is at risk and oil and gas markets are in turmoil,” said Sadad Ibrahim Al Husseini, former chief executive of Saudi Arabia’s national oil company Aramco .

In the first five months of this year, Russia’s revenue from oil and gas, the biggest contributor to its budget, was half that of the same period in 2022, it said the country’s Ministry of Finance.

Ariel Ahram, a Middle East expert at Virginia Tech, said Middle East manufacturers had hoped demand from China would pick up once it emerged from the Covid lockdown, but were disappointed. With oil prices down below what they were when Russia invaded Ukraine, Saudi Arabia and its allies must hold Russia captive.

“Leaning to Russia is a way of waiting,” Mr. Ahram said.

But some representatives of the Middle East are already complaining about the reliability of Russia as a partner. One point of contention is that Russia has not released its energy production figures since April. Many analysts said Russia’s seaborne oil exports appeared to be rising, offsetting the loss of oil sold to Europe through the pipeline.

“For the alliance to be effective, it needs to make its data public,” said Marcel Salikhov, director of the Institute of Energy and Finance in Moscow. “Russia has closed its data and that creates contradictions.”

Vivian Nereim contributed reporting.