Iran's supreme leader vowed to teach the United States "unforgettable lessons" on Saturday, as Washington reported its first military deaths since renewing its hostilities with the Islamic republic.A month after the foes signed a now-abandoned preliminary deal aimed at ending their war, Tehran struck infrastructure around the Gulf in retaliation for a week of intensifying US attacks, which Iran said had hit an airport, a railway station and bridges.Iran hit an oil facility in Kuwait as well as a power and water plant, authorities in the Gulf state said, while in Bahrain the army said air defences repelled a wave...