US President Donald Trump has suggested that American forces could take control of Iran's Kharg Island, the country's main oil export terminal in the Persian Gulf.
Qatar strongly condemned the Iranian strikes on a power station and desalination plant in Kuwait that killed an Indian worker.
The conflict has put global oil and gas supplies at risk, led to shortages of fertilisers, and affected air travel.
Iran's control over the Strait of Hormuz has unsettled markets and pushed up prices, as the route carries about one-fifth of the world's oil trade.
Trump says deal with Iran could be 'very soon', but the war has killed more than 4,500 people, with about three-quarters of the deaths in Iran.
