Iran's Defence Minister Hossein Dehghan has warned that all of Saudi Arabia would be destroyed with the exception of Mecca and Medina if the theocratic kingdom chooses to make any "ignorant" move in the fragile Middle East region. His comments come as a sharp rebuke to Saudi Arabia's Deputy Crown Prince Mohammed bin Salman, who warned of moving the "battle" to Iran.

Iran, a Shia-dominated regional heavyweight, has a fractious relationship with the Sunni powerhouse. Their relations are strained over a series of religio-political issues such as the way Islam is interpreted, the Islamic world's leadership and oil exports. Tensions between the two countries escalated after Riyadh sentenced 47 people to death including a prominent Shia cleric, Nimr al-Nimr in January 2016.

In the latest incident, Dehghan cautioned the conservative Saudi kingdom on Sunday (7 May) to tread carefully in sensitive geopolitical matters. "We warn them against doing anything ignorant, but if they do something ignorant, we will leave nowhere untouched apart from Mecca and Medina," the Iranian minister said in an interview to the Arabic-language Al-Manar TV, referring to the two key sites in Saudi Arabia that are considered holy by Muslims.

He was responding to the blunt comments made by the Saudi prince — who is also the defence minister — when he ruled out any kind of ties with Iran. "We know that we are a main goal for the Iranian regime. We will not wait until the battle becomes in Saudi Arabia but we will work to have the battle in Iran rather than in Saudi Arabia," Mohammed bin Salman said.

Both Iran and Saudi Arabia are engaged in a bitter proxy conflict in Yemen, where the Shia-aligned Houthi rebels are backed by Tehran. The rebels are being pounded by Saudi forces in the fight to capture control of Yemen.