As Saudi Arabia prepared to host a summit of Gulf Arab leaders on Tuesday, political commentators in the neighboring United Arab Emirates began furiously dropping hints online that major news was coming.

For weeks, Emirati officials had been openly expressing frustration with their Arab neighbors, complaining about their weak stance toward Iran, which had fired thousands of missiles and drones at Gulf countries in response to U.S. and Israeli bombing. Analysts wondered if the Emirates would demonstrate that displeasure at the summit.

Then, just as the Saudi Crown Prince, Mohammed bin Salman, commenced the meeting, the Emirati government dropped a bombshell from hundreds of miles away: it announced that it was leaving OPEC, a cartel of oil-producing countries that wields sway over global energy prices.

Emirati officials said they were doing so in order to unilaterally increase their oil production and meet the market’s long-term needs, but the fact that OPEC’s de facto leader is Saudi Arabia was lost on no one in the region.

Whether the timing of the announcement was intentional or coincidental, it was a potent symbol of the recent, tectonic shifts reshaping the Middle East, which have only accelerated during the war. By pulling away from OPEC, the Emirati government demonstrated that is willing to make dramatic moves in its own interests, and will not be constrained by traditional alliances and conventions.

“It is an Emirati declaration of independence,” said Kristin Diwan, a senior resident scholar at the Arab Gulf States Institute in Washington, a research organization. “They no longer feel beholden to institutions that don’t align with their interests.”

The advent of an unbound Emirates has implications for markets, economies and conflicts around the world. With more than $2 trillion in sovereign wealth, the tiny country has cultivated influence far beyond its borders.

In an interview with The New York Times on Tuesday, the Emirati energy minister, Suhail Al Mazrouei, suggested that the decision to withdraw from OPEC had “nothing to do with any specific producer.” Saudi Arabia and the Emirates are “brothers,” standing together during the crisis caused by the war, he added.

Yet it is undeniable that the Emirates — a major oil exporter and close U.S. ally — has increasingly been going its own way in the region.

“What we’re seeing today is like a new U.A.E.,” said Abdulkhaleq Abdulla, a prominent Emirati political scientist. “This is how the U.A.E. will be behaving, and will be conducting itself regionally, globally.”

In recent years, Emirati officials have spoken of the importance of pursuing their own economic interests, chafing at quotas set by OPEC that curtailed their oil production.

They have deepened their alliance with Israel, while other Arab governments keep their distance or pull further away from it.

In Yemen, the Emirates has supported an armed insurgency, angering Saudi leaders, who back the government there.

And in Sudan’s brutal civil war, where Saudi Arabia and Egypt support the government, the Emirates has backed a rival paramilitary group. Emirati officials have denied sending weapons to the Sudanese group, the Rapid Support Forces, despite extensive evidence to the contrary.

The rift between Saudi Arabia and the Emirates that has been developing for years and extends to the highest levels of the two governments.

Prince Mohammed of Saudi Arabia and the Emirati leader, Sheikh Mohammed bin Zayed, were once close partners, joining forces in 2015 to fight the Houthi rebels in Yemen, but they have since diverged significantly, pursuing different visions for the future of the Middle East that have come into conflict with one another. That rupture burst into public view in December, but appears to have hardened during the war with Iran.

Since the U.S.-Israeli assault began on Feb. 28, Iran has directed the brunt of its retaliation at Gulf countries that host American military installations.

Instead of uniting the Gulf states against a common enemy, the Iranian attacks appear to have helped splinter the region.

As Gulf Arab officials weigh how to respond to Iran, the Emirates has taken measures to sever its longstanding cultural and economic ties with the country. Saudi Arabia, which has faced fewer and less damaging attacks, has condemned Iran strongly, but has supported efforts led by Pakistan to find a diplomatic resolution to the war — an initiative from which the Emirates has kept some distance.

Emirati officials have spoken repeatedly of their dissatisfaction with Arab and Islamic multilateral organizations, hinting that they would have preferred a stronger stance against Iran.

“Every Gulf state had its own policy of containment toward Iran, and all of those containment policies have failed,” Anwar Gargash, a senior Emirati official, said at a conference in Dubai on Monday. “All our policies have failed miserably.”

Gulf solidarity “was not at the level of the challenge” that the war presented, he said.

The Gulf countries are also reckoning with how to handle their relationship with the United States, which could not fully protect them from the barrage of Iranian attacks, despite bein0g their main security guarantor for decades.

“All of the states in the region have been adapting to the fact that the United States is not going to provide the kind of security umbrella that they had come to appreciate,” Ms. Diwan said. “It requires each state to kind of chart its own direction — and they haven’t been able to align.”

These trends coalesced with Tuesday’s announcement.

For years, oil policy has been a visible source of tensions between the Emirates and Saudi Arabia. The Emirates appears to favor a strategy of maximizing its oil production — in effect, selling as much of its oil as it can before energy markets move on from fossil fuels.

On the other hand, Saudi Arabia generally seeks higher oil prices in the long term, a strategy that sometimes requires constraining the production of OPEC members, including the Emirates.

A much larger and more oil-dependent country, Saudi Arabia needs higher revenue in order to fund its government budget, as well as the crown prince’s ambitious and expensive plans to turn the kingdom into a business and tourism hub.

“While Saudi Arabia aims to sustain oil markets for the next century, the U.A.E. feels no such urgency,” said Bachar El-Halabi, senior analyst in Dubai for Argus Media, a commodities research firm.

The decision to withdraw from OPEC and increase oil production — even if the Emirates faces barriers to exporting more barrels as long as the war continues — could also please Trump administration officials, who are facing political pressure from high energy prices.

Reflecting their government’s desire to chart its own course, Emirati officials and pro-government commentators have been speculating about what could come next. Some say the Emirates could withdraw from the Arab League, the Gulf Cooperation Council or the Organization of Islamic Cooperation, all of which are regional multilateral groups.

Mr. Abdulla, the political scientist, said he would not rule out a decision on the Arab League soon — perhaps a freeze of membership or a halt on Emirati financing to the organization, if not a total withdrawal.

For years, the Emirates had remained in OPEC “out of deference to Saudi Arabia,” Ms. Diwan said. Tuesday’s news makes it clear that “they will no longer defer to Saudi leadership.”

Tareq al-Otaiba, an Emirati fellow at Harvard University’s Belfer Center, had foreshadowed the withdrawal from OPEC in an essay on “the hollow promise of Arab solidarity,” published last week.

“The war has shown which were true friends,” Mr. al-Otaiba wrote.

“The question is not whether Abu Dhabi will remember,” he added, referring to the Emirati capital. “It is what the Arab world will look like when the U.A.E. decides to move on.”

Rebecca F. Elliott contributed reporting from New York.