As Iran and Israel trade strikes and the US weighs joining in, wealthy Gulf states on the conflict's doorstep are engaged in frantic diplomacy to halt the war -- but solutions remain elusive.

A spillover of the conflict or the Iranian government's collapse are both worrying outcomes for the energy-rich region, which hosts several major US military bases.

Peace and stability have been central to the rise of Gulf powers including Qatar, Saudi Arabia and the United Arab Emirates, who are pivoting their economies towards business and tourism.

The Dutch captain of a Gaza-bound ship carrying activists including Swedish campaigner Greta Thunberg said Wednesday future missions could still be in the works as he returned to the Netherlands.

Mark van Rennes arrived back at Amsterdam's Schiphol Airport, greeted by dozens of supporters, some carrying Palestinian flags and banners reading "Free Palestine."

His ship, the Madleen, operated by the Freedom Flotilla Coalition, left Italy on June 1 with the aim of delivering aid and challenging the Israeli blockade of Gaza.

US President Donald Trump said Wednesday he was still deciding whether to join Israel's strikes on Iran, claiming Tehran now wants talks at the White House but may have waited too long.

Trump held his second Situation Room meeting in two days with his national security team as he left the world guessing about his potential order of military action.

"I may do it, I may not do it. I mean, nobody knows what I'm going to do," Trump told reporters at the unveiling of one of two giant new flagpoles at the White House.

Near the once-bustling Iraqi border crossing of Bashmakh, Iranian driver Fatah stocked up on rice, sugar and tea, staples that have become increasingly hard to get back home.

Fatah -- who like others in this story is being identified by a pseudonym -- was among dozens of truck drivers waiting impatiently to cross back into Iran from Iraq's northern Kurdistan region, hauling not only their commercial cargo, but also essential goods for their families after days of Israeli attacks.

Israel and Iran exchanged fire again on Wednesday, the sixth day of strikes in their most intense confrontation in history, fuelling fears of a drawn-out conflict that could engulf the Middle East.

Here are the latest developments:

- New missile salvo -

Israel's army on Wednesday said it had detected new missiles launched from Iran, adding that its defensive systems were operating to intercept the threat.

The United States is "complicit" in Israel's strikes in Iran, Tehran's ambassador to the United Nations claimed Wednesday, vowing that his country would respond if Washington crosses a "red line".

After decades of enmity and a prolonged shadow war, Israel says its surprise air campaign that began on June 13 is aimed at preventing Iran from acquiring nuclear weapons -- an ambition Tehran denies.

Iran said early Wednesday that it fired hypersonic missiles at Israel in the latest round of overnight strikes between the arch foes.

Vladimir Putin is eyeing the conflict between Israel and Iran as an opportunity to thrust himself to the forefront of the international stage, more than three years into his invasion of Ukraine.

The Russian president has pitched himself as a possible mediator -- though Moscow's closeness to Iran and Russia's invasion of Ukraine raise doubts about what kind of role he can play, experts say.

The assault on Ukraine and the war in Gaza have strained Moscow's traditionally good relations with Israel, home to a large Russian-born community.

Iran's supreme leader Ayatollah Ali Khamenei said Wednesday the nation would never surrender and warned the United States of "irreparable damage" if it intervenes, while Israel said it had destroyed the internal security headquarters in Tehran.

Khamenei's speech came six days into the conflict, with Trump saying he may or may not intervene in the conflict, while demanding Iran's "unconditional surrender".

The long-range blitz began Friday, when Israel launched a massive bombing campaign that prompted Iran to respond with missiles and drones.

Gaza's civil defence agency said 33 people were killed by Israeli fire in the Palestinian territory on Wednesday, including 11 who were seeking aid.

The war sparked by Hamas's October 2023 attack on Israel has ravaged the Gaza Strip and resulted in severe shortages of food, fuel and clean water.

Civil defence spokesman Mahmud Bassal told AFP that 11 people were killed and more than 100 wounded "after the occupation forces opened fire and launched several shells... at thousands of citizens" who had gathered to queue for food in central Gaza.

A powerful American bunker-busting bomb is the only weapon capable of destroying Iran's deeply buried nuclear facilities, making it President Donald Trump's weapon of choice if he chooses to militarily back Israel.

The GBU-57, a 30,000-pound (13,607 kg) warhead capable of penetrating 200 feet (61 meters) underground before exploding, is missing from Israel's arsenal despite its stated goal of preventing Iran from building a nuclear bomb.

- Why this bomb? -