Iran launched a wave of missiles and drones at Kuwait and Bahrain overnight, killing at least one person and wounding 63 at Kuwait International Airport, in one of the most dangerous escalations since a ceasefire halted open warfare in the Gulf earlier this year. Kuwait's defence ministry said its forces shot down 13 ballistic missiles and 17 drones, but that not every projectile was intercepted before it reached the country's main civilian airport.

The person killed at the airport was an Indian national, one of the large community of foreign workers in the emirate, and most of the injured were also caught in or near the terminal complex. Kuwait Airways suspended operations during the attack and resumed flights only after the airport was cleared and inspected, while Kuwait summoned Iran's acting chargé d'affaires and expelled two Iranian diplomats in protest.

In neighbouring Bahrain, home to the headquarters of the US Navy's Fifth Fleet, the defence force said it intercepted three Iranian missiles and several drones aimed at civilian facilities. No deaths were reported there, but the targeting of two Gulf monarchies that host American forces widened a conflict that had previously centred on Iran, Israel and shipping lanes.

The United States responded with strikes of its own. American forces hit targets on Qeshm Island, off Iran's southern coast, and a US fighter disabled an oil tanker, the Botswana-flagged M/T Lexie, near Kharg Island, according to military officials. The tit-for-tat blows came as Washington insisted it was still pursuing a diplomatic settlement, with Secretary of State Marco Rubio telling Congress that Tehran had agreed to negotiate aspects of its nuclear programme even as it moved to disrupt traffic through the Strait of Hormuz.

Iran has framed its actions as retaliation for Israel's expanding military operations in Lebanon and Gaza and for what it calls an illegal US naval presence in the Gulf. By striking Kuwait and Bahrain rather than Israel directly, Tehran put pressure on Washington through its regional partners while stopping short of the kind of attack on Israeli soil that could trigger a far larger war.

The escalation rattled energy markets, where crude prices climbed on fears that the world's most important oil choke point could be drawn further into the fighting. Roughly a fifth of globally traded oil passes through the Strait of Hormuz, and each new strike near the waterway revives the risk premium that diplomats had spent weeks trying to drain away.

For the Gulf states, long accustomed to hosting American bases while trading with all sides, the night's events were a stark reminder of their exposure. Whether the exchange hardens into a new phase of the war or gives way to renewed negotiation is likely to depend on how forcefully Washington answers and whether the fighting in Lebanon, which Tehran cites as its grievance, continues to spread.