In May 2017, Trump declared a shift in US foreign policy toward favoring Saudi Arabia at Iran's expense, marking a departure from President Obama's more reconciliatory approach.
This move came days after the re-election of Rouhani in Iran, who defeated conservative candidate Ebrahim Raisi.
Rouhani's victory was seen as a popular mandate for liberal reforms in the country.

Several incidents in mid-2017 further heightened tensions.
In May 2017, Saudi forces laid siege on Al-Awamiyah, the home of Nimr al-Nimr, in a clash with Shia militants.
Dozens of Shia civilians were reportedly killed.
Residents are not allowed to enter or leave, and military indiscriminately shells the neighborhoods with artillery fire and snipers are reportedly shooting residents.
In June, the Iranian state-owned news agency Press TV reported that the president of a Quran council and two cousins of executed Nimr al-Nimr were killed by Saudi security forces in Qatif.
During the subsequent crackdown the Saudi government demolished several historical sites and many other buildings and houses in Qatif.
On 17 June, Iran announced that the Saudi coast guard had killed an Iranian fisherman.
Soon after, Saudi authorities captured three Iranian citizens who they claimed were IRGC members plotting a terrorist attack on an offshore Saudi oilfield.
Iran denied the claim, saying that those captured are regular fishermen and demanding their immediate release.

 
In the wake of the June 2017 Tehran attacks committed by ISIL militants, the Iranian Revolutionary Guard Corps issued a statement blaming Saudi Arabia, while Saudi Foreign Minister Adel al-Jubeir said there was no evidence that Saudis were involved.
Later Iranian official Hossein Amir-Abdollahian stated that Saudi Arabia is the prime suspect behind the Tehran attacks.
The commander of IRGC, Major General Mohammad Ali Jafari, claimed that Iran has intelligence proving Saudi Arabia's, Israel's, and the United States' involvement in the Tehran attack.
Iran's Supreme Leader Ayatollah Khamenei later accused the United States of creating ISIL and of joining Saudi Arabia in funding and directing ISIL in addition to other terrorist organizations.

In October 2017, the government of Switzerland announced an agreement in which it would represent Saudi interests in Iran and Iranian interests in Saudi Arabia.
The two countries had severed relations in January 2016.

Several major developments occurring in November 2017 drew concerns that that proxy conflict might escalate into a direct military confrontation between Iran and Saudi Arabia.
On 4 November the Royal Saudi Air Defense intercepted a ballistic missile over Riyadh International Airport.
Foreign Minister Adel al-Jubeir asserted that the missile was supplied by Iran and launched by Hezbollah militants from territory held by Houthi rebels in Yemen.
Crown Prince Mohammad bin Salman called it "direct military aggression by the Iranian regime" and said that it "may be considered an act of war against the kingdom".
Also on 4 November, the Prime Minister of Lebanon resigned, sparking a political crisis seen as part of a Saudi effort to counteract Iran's influence in the country.
Bahrain also blamed a 10 November explosion on its main oil pipeline on Iran.

On 24 November 2017, Dubai's security chief Lieutenant General Dhahi Khalfan blamed the 2017 Sinai attack on Al-Jazeera and called for bombing of the network by a Saudi-led coalition.
In late November 2017, IRGC commander Jafari said revolutionary Islamic paramilitary forces had formed across the Middle East and surrounding regions to counter the influence of ultraconservative militant jihadi groups and Western powers.

In 2017 Saudi Arabia funded the creation of the Persian language satellite TV station Iran International, operated from London.
In May 2017, Trump declared a shift in US foreign policy toward favoring Saudi Arabia at Iran's expense, marking a departure from President Obama's more reconciliatory approach. This move came days after the re-election of Rouhani in Iran, who defeated conservative candidate Ebrahim Raisi. Rouhani's victory was seen as a popular mandate for liberal reforms in the country.
Several incidents in mid-2017 further heightened tensions. In May 2017, Saudi forces laid siege on Al-Awamiyah, the home of Nimr al-Nimr, in a clash with Shia militants. Dozens of Shia civilians were reportedly killed. Residents are not allowed to enter or leave, and military indiscriminately shells the neighborhoods with artillery fire and snipers are reportedly shooting residents. In June, the Iranian state-owned news agency Press TV reported that the president of a Quran council and two cousins of executed Nimr al-Nimr were killed by Saudi security forces in Qatif. During the subsequent crackdown the Saudi government demolished several historical sites and many other buildings and houses in Qatif. On 17 June, Iran announced that the Saudi coast guard had killed an Iranian fisherman. Soon after, Saudi authorities captured three Iranian citizens who they claimed were IRGC members plotting a terrorist attack on an offshore Saudi oilfield. Iran denied the claim, saying that those captured are regular fishermen and demanding their immediate release.
 
In the wake of the June 2017 Tehran attacks committed by ISIL militants, the Iranian Revolutionary Guard Corps issued a statement blaming Saudi Arabia, while Saudi Foreign Minister Adel al-Jubeir said there was no evidence that Saudis were involved. Later Iranian official Hossein Amir-Abdollahian stated that Saudi Arabia is the prime suspect behind the Tehran attacks. The commander of IRGC, Major General Mohammad Ali Jafari, claimed that Iran has intelligence proving Saudi Arabia's, Israel's, and the United States' involvement in the Tehran attack. Iran's Supreme Leader Ayatollah Khamenei later accused the United States of creating ISIL and of joining Saudi Arabia in funding and directing ISIL in addition to other terrorist organizations.
In October 2017, the government of Switzerland announced an agreement in which it would represent Saudi interests in Iran and Iranian interests in Saudi Arabia. The two countries had severed relations in January 2016.
Several major developments occurring in November 2017 drew concerns that that proxy conflict might escalate into a direct military confrontation between Iran and Saudi Arabia. On 4 November the Royal Saudi Air Defense intercepted a ballistic missile over Riyadh International Airport. Foreign Minister Adel al-Jubeir asserted that the missile was supplied by Iran and launched by Hezbollah militants from territory held by Houthi rebels in Yemen. Crown Prince Mohammad bin Salman called it "direct military aggression by the Iranian regime" and said that it "may be considered an act of war against the kingdom". Also on 4 November, the Prime Minister of Lebanon resigned, sparking a political crisis seen as part of a Saudi effort to counteract Iran's influence in the country. Bahrain also blamed a 10 November explosion on its main oil pipeline on Iran.
On 24 November 2017, Dubai's security chief Lieutenant General Dhahi Khalfan blamed the 2017 Sinai attack on Al-Jazeera and called for bombing of the network by a Saudi-led coalition. In late November 2017, IRGC commander Jafari said revolutionary Islamic paramilitary forces had formed across the Middle East and surrounding regions to counter the influence of ultraconservative militant jihadi groups and Western powers.
In 2017 Saudi Arabia funded the creation of the Persian language satellite TV station Iran International, operated from London.
Iran–Saudi Arabia proxy conflict