Saudi Arabia will strike those who threaten the kingdom's security and stability with an "iron fist", the crown prince said on Thursday, one day after an attack on a Remembrance Day ceremony injured two in the kingdom. Islamic State claimed Wednesday's attack on a non-Muslim cemetery in the Saudi Red Sea city of Jeddah during a World War One remembrance ceremony involving French and other embassies. "We will continue to hit with an iron fist against anyone who thinks of threatening our security and stability," Crown Prince Mohammed bin Salman, the kingdom's de facto ruler, said in a speech carried by Saudi state news agency SPA.