At this week’s meeting of the UN General Assembly—convened in the wake of the September 14 attack on the heart of Saudi Arabia’s oil and gas industry—Iran’s Foreign Minister Javad Zarif is making it clear that Tehran is ready to play hardball.

Speaking at Iran’s UN Mission on Sunday to a small group of reporters, including a writer for The Nation, Zarif struck a defiant tone, saying that Iran would not meet or negotiate with President Trump or Secretary of State Mike Pompeo—the latter, Zarif says, ought to be brought up on charges at the International Criminal Court for attempting to starve Iran into submission. Zarif demanded that the Europeans, including Britain, France, and Germany, three signatories to the 2015 accord on Iran’s nuclear program that has been abandoned by the United States, live up to their legal responsibility under the terms of that accord by ignoring or breaking US economic sanctions on Iran. And he called on the world’s major non-American oil firms, including Total, ENI, BP, Shell, and Sinopec, to resume purchases of Iranian oil exports in defiance of US “bullying.”

Underscoring the importance of that challenge, Zarif made it clear that Iran won’t guarantee the safety and security of the nearly one-third of the world’s oil supply that passes out of the Persian Gulf through the Strait of Hormuz. “We will not invest in the security of the Persian Gulf if it is not secure for us,” said Zarif. “If we cannot sell our oil, why should we invest in other people’s security?” Iran, he said, “has to be able to do business.”

Those words took on special meaning in the aftermath of the September 14 volley of armed drones and cruise missiles that blew apart Saudi Arabia’s Abqaiq and Khurais oil and gas facilities. Whether that attack was launched from inside Iran, from pro-Iranian militia forces in Iraq, or by Iran-allied Yemeni forces, it’s virtually certain that the devastating raid was a message from Tehran to the United States, Saudi Arabia, and the rest of the world that Iran would not sit by passively in response to Trump and Pompeo’s effort to isolate and strangle it.

While both Trump and Pompeo have blamed Iran for the attack, with Pompeo calling it “an act of war,” Iran has repeatedly denied any and all responsibility for it, and in his meeting with reporters Zarif unconvincingly repeated those denials. “It wasn’t Iran,” he said flatly. Gesturing demonstratively throughout his 75-minute press meeting, jabbing his finger repeatedly to emphasize his points, a confident-seeming Zarif claimed not to have any idea who carried it out, though he also implied that it was done by Yemen’s Houthi fighters, who are backed by Tehran, on their own. In doing so, he was delighted to point out that the tens of billions of dollars in US military equipment and technology that Washington has showered on Riyadh in recent years was incapable of either detecting or preventing the incoming fire. “The beautiful American equipment did not enable them to shoot down very primitive Yemeni weapons,” says Zarif.

For both Washington and Riyadh, that is in fact a game-changer. By all accounts, the attack stunned the Saudi leadership, whose youthful crown prince and defense minister, Mohammed bin Salman, has been the leader of the anti-Iran push for years. But if an attack such as the one that closed down approximately half of Saudi Arabia’s enormous oil output, instantly depriving the world of 5 percent of its supply, could happen so easily, it may have convinced the Saudi king and his son, the crown prince, to tread far more carefully in confronting Iran—and perhaps Saudi Arabia is passing its fears on to the United States. This creates an unpleasant dilemma for the White House: Can the United States afford to retaliate by striking Iran militarily if, as it appears, Iran and/or its proxies will shoot back? Just days ago, Zarif told CNN that for the United States to attack Iran now will mean “all-out war.”

During the UN General Assembly, Iran plans to launch a diplomatic offensive aimed at convincing European nations and other world powers, in particular, to stand up to the United States. According to Zarif, President Hassan Rouhani will meet individually with British Prime Minister Boris Johnson, French President Emmanuel Macron, Japanese Prime Minister Shinzo Abe, and possibly German Chancellor Angela Merkel. Perhaps as a signal of its willingness to calm tensions with Iran’s European partners in the 2015 nuclear agreement, today Tehran released a British-flagged oil tanker that it had seized in the Strait of Hormuz two months ago, a tit-for-tat action after Britain freed an Iranian tanker a few weeks ago.

In addition, on Wednesday morning, the Iranian leaders will take part in a critical meeting with the remaining signers of the nuclear accord, known as the Joint Comprehensive Plan of Action: Britain, France, Germany, Russia, and China. Zarif said there will be a place open for the United States to rejoin the group—and to reaffirm the JCPOA, which Trump abandoned in 2018—but he added that he has zero expectation that the United States will do so. Instead, Iran will use the meeting to remind the Europeans that it is their responsibility to preserve what’s left of the agreement—including their own promises to expand trade, commerce, and technology-sharing with Iran, despite the American campaign of “maximum pressure.” According to Zarif, if the five big non-US oil firms mentioned above defiantly resume open purchases of Iranian oil, the United States can do nothing to stop them.

By quitting the JCPOA, Trump has convinced Iran’s population that there is little or no value in negotiating with the United States, said Zarif. “If you ask the population [of Iran] what they think about engagement, they will say that they don’t believe in it.” And the new US sanctions have seriously undermined Iran’s economy, according to Zarif, who acknowledged a 75 percent fall in the value of Iran’s currency and a year-to-year decline of 6 percent in Iran’s overall economic output. Still, he added, “My job, as a diplomat, is to seek a peaceful way out.”

Rouhani, who will speak to the UNGA on Wednesday, plans to propose what Zarif called a “coalition of hope.” That, said Zarif, would be a Persian Gulf–wide security agreement, involving Iran, Iraq, Saudi Arabia, and the other Gulf states in an accord that would ensure freedom of navigation, a pact on nonaggression, an agreement to seek nonintervention by outside powers, a plan for energy security, and other confidence-building measures, endorsed by the five permanent members of the UN Security Council—including the United States. It’s a long shot, some would say a nonstarter. Still, it might be a first step in defusing the tensions that have swept across the Gulf since Trump quit the JCPOA.