Iran has unveiled an underground naval missile base in an undisclosed location in the Gulf, just days before the start of Donald Trump's second term as president. The unveiling comes amid rising tensions with the US, as Iranian leaders fear that Trump may authorize strikes on their nuclear sites and tighten sanctions on their oil industry. The base is one of several built underground for vessels capable of launching long-range missiles and conducting distant warfare. Iran has previously unveiled underground 'missile cities' and is currently engaged in military exercises that include defending nuclear installations against mock attacks.