US Secretary of State John Kerry has warned Iran over its alleged support for Shia Houthi rebels in Yemen. He said the US would support any Middle Eastern country that felt threatened by Iran, and would not “stand by” if Iran destabilised the region. Speaking to PBS Newshour, Mr Kerry said it was clear Iran was aiding the Houthis: There are obvious supplies that have been coming from Iran. There are a number of flights every single week that have been flying in,” he said. “Iran needs to recognise that the US is not going to stand by while the region is destabilised or while people engage in overt warfare across lines, international boundaries and other countries,” he added. Fighting has intensified in the southern Yemeni city of Aden between the Houthis and militia men loyal to President Abedrabbo Mansour Hadi. At least 22 people were reportedly killed on Wednesday by shelling in two residential districts in Aden. On Wednesday, boats carrying aid managed to arrive in Aden for the first time since the Saudi led air strikes began.