Saudi Arabia

Iran
Bilateral relations were strained over different geopolitical issues, such as the interpretations of Islam, aspirations for leadership of the Islamic world, oil export policy, relations with the U.S. and the West, and nuclear programs.

On January 3, 2016, angry Iranian protesters stormed Saudi Arabia's embassy in Tehran to protest against Saudi Arabia's execution of Nimr al-Nimr, a prominent Shia cleric from the kingdom's Shia minority, and 46 others the previous day. In response, Saudi Arabia cut diplomatic ties, accusing Iran of destabilizing the region by creating "terrorist cells" in Saudi Arabia.

Yemen
As Iranian-backed Shia Houthi forces advanced on the southern base of the U.S.-supported President Hadi in Yemen, Saudi Arabia joined the conflict in a coalition of ten nations on March 25, 2015, launching an air campaign to support Hadi in the fight against the Houthis. Against the backdrop of the escalating conflict, Sunni Muslim extremists pledged allegiance to both al-Qaeda and the Islamic State, escalating sectarian assaults on the Houthis. The Saudi coalition pushed back Houthi forces, with fighting into the fall of 2015 focusing on the cultural city of Taiz after the southern port city of Aden was retaken by Hadi forces in July. Throughout the fall of 2015, planes and gunboats from the Saudi-led coalition bombarded targets in northern Yemen, allowing troops loyal to Hadi to seize areas in mid-December 2015. The U.N. noted that the campaign in Yemen was responsible for a disproportionate amount of attacks on civilian areas. Attempts to negotiate peace were disrupted as fragile ceasefires were violated many times. The last ceasefire of 2015, which began on December 15, ended on January 2, 2016.

Executions
The execution of 47 people - including a vocal Shia cleric, three other Shias, and 43 members of al-Qaeda, sparked angry protests in the Qatif region in eastern Saudi Arabia, where demonstrators denounced the ruling Al-Saud dynasty, and in the nearby Gulf kingdom of Bahrain. Despite the focus on the cleric, the executions seemed mostly aimed at discouraging jihadism in Saudi Arabia, where dozens had died in 2015 in attacks by Sunni militants.