Tensions between the US and Iran have been high recently, following the killing of Iranian General Qasem Soleimani by the US in Baghdad. Iran declared it would no longer abide by any of the restrictions imposed by the 2015 nuclear deal, and President Donald Trump threatened that the US could strike back at Iran in the event of retaliation for Soleimani's death "in a disproportionate manner". So what is happening, and why? 5 Live's Nicky Campbell put your questions to a panel of experts: Jonathan Marcus, BBC Diplomatic Correspondent; Martin Lanni, former Royal Navy Liaison officer to the US Fifth Fleet in the Middle-East; global politics writer Tim Marshall; Emma Sky, US military political advisor and Middle Eastern politics lecturer; and Dr Aniseh Bassiri Tabrizi from defence thinktank RUSI.