UN Secretary-General Antonio Guterres on Thursday warned that ongoing restrictions to navigation in the Strait of Hormuz could tip the world into recession, stating that navigational rights and freedoms "must be restored immediately".

Speaking at a news conference hosted at UN headquarters in New York, the UN chief listed three scenarios tied to the duration of the Middle East crisis, which is entering its third month.

In the best case, if the restrictions are lifted today, global growth would still fall from 3.4 to 3.1 percent this year, with inflation rising to 4.4 percent, Guterres said.

If the crisis extends through midyear, 32 million people could be pushed into poverty and 45 million more could face extreme hunger, said Guterres. And if it persists through year-end, global growth could collapse to 2 percent and inflation surpass 6 percent, he said.

"These consequences are not cumulative. They are exponential," said Guterres, adding that developing countries will be hit the hardest.

The secretary-general called on all parties to comply with Security Council Resolution 2817. "Open the Strait. Let all ships pass," he said.

"Now is the time for dialogue, for solutions that pull us back from the brink, and for measures that can open a pathway to peace," Guterres said. "The world is waiting."

The warning comes amid escalating tensions following a breakdown in post-ceasefire talks between the United States and Iran earlier this month.

Two months into the US-Israeli war with Iran, the vital sea channel remains closed, choking off 20 percent of the world's oil and gas supplies. That has sent global energy prices surging and heightened concerns about the risks of an economic downturn, Reuters reported on Thursday.

Iran said on Thursday it would respond with "long and painful strikes" on US positions if Washington renewed attacks, and also restated its claim to the Strait of Hormuz, complicating US plans for a coalition to reopen the waterway.

US President Donald Trump was slated to receive a briefing on Thursday on plans for a series of fresh military strikes on Iran to compel it to negotiate an end to the conflict, a US official told Reuters.

Such options have long been part of US planning but reports of the proposed briefing, first issued by news site Axios late on Wednesday, initially spurred big gains in oil prices, ?with the benchmark Brent crude contract hitting more than $126 a barrel at one point. It later slipped back to around $114.

Negotiations held in Islamabad, Pakistan on April 11 and 12 failed to produce an agreement, after which Washington imposed a blockade on Iranian ports, while Iran threatened maritime traffic, preventing tankers from transiting through the Strait of Hormuz.

A ceasefire between Iran, the US and Israel took effect on April 8 after 40 days of fighting that began on Feb 28 with strikes on Tehran and other Iranian cities.

Iranian officials said the attacks killed senior leadership figures, including then-Supreme Leader Ali Khamenei, as well as civilians. Iran responded with missile and drone strikes targeting Israel and US assets in the region and later moved to restrict traffic through the Strait.

Iranian President Masoud Pezeshkian on Thursday said any attempt by the US to impose a naval blockade would be "doomed to failure," according to a statement published on his office's website, Xinhua reported.

In a statement marking Persian Gulf National Day, Pezeshkian said regional waterways should not be subject to "unilateral foreign will", and called instead for collective security based on mutual respect among coastal states.

Xinhua and Reuters contributed to the story.

minluzhang@chinadailyusa.com