A fire at a pipeline run jointly by Saudi Arabia and Bahrain has been called a terrorist attack sponsored by Iran by the Bahrainian interior minister. In response, Saudi Arabia immediately increased security at its own oil facilities. The pipeline attack follows a missile attack on the Riyadh International Airport that was foiled by Saudi defenses. 

Bloomberg:

The plan to step up security was reported by Al-Arabiya television Saturday, citing the Saudi energy ministry. Bahrain’s Interior Ministry said recent terrorist activities in Bahrain were directed by Iran, and security forces determined that the fire was intentional. The pipeline later in the day resumed pumping oil after a brief halt, the state-run Bahrain News Agency reported, citing a statement by Bahrain Petroleum Co.

The "attempt to bomb the Saudi-Bahraini oil pipeline is a dangerous Iranian escalation that aims to scare citizens and hurt the global oil industry," Bahrain’s Foreign Minister Khalid Al-Khalifa said on Twitter. Iran responded by saying the Bahrainis “need to know that the era for lies and childish finger-pointing is over," official Islamic Republic News Agency reported on Sunday, citing Foreign Ministry spokesman Bahram Qassemi.

Tensions have been rising in the region after Saudi Arabia blamed Shiite-ruled Iran for an attempted missile attack on Riyadh’s international airport last week, saying it could be considered an act of war. Saudi Arabia said the thwarted missile launched by Yemeni rebels had Iranian markings, a charge Iran has denied.

The missile attack, the attack on the pipeline, and the forced resignation of Lebanon's Prime Minister Saad Hariri are only the latest in a series of events that have caused tensions to skyrocket in the region and make war between Saudi Arabia and Iran more likely.

Guardian:

Within hours Hariri, by then in Riyadh in Saudi Arabia, had resigned his position, concluding his transition from Lebanese leader to Saudi envoy and Lebanon’s transformation from outpost to ground zero of a stunning regional escalation.

The aftermath of the hurried departure, and the heated week since, has swept across the region, linking apparently disparate events which, in reality, were symptoms of political undercurrents that had been coursing through the Middle East for generations, and which have now burst to the surface.

The fall of Kurdish-held Kirkuk in northern Iraq to the Iraqi government, backed by Iran’s most prominent general, in October, starvation among the population of war-torn Yemen, a ballistic missile over Riyadh, and the apparently forced exit of the premier in Lebanon are all part of the same machinations – a great strategic power play between two regional heavyweights that has suddenly shifted from back rooms to potent realisation.

Now, more than at any point in modern history, Iran and Saudi Arabia are squared off against each other as a race to consolidate influence nears a climax from Sana’a to Beirut and the tens of thousands of miles in between.

The standoff is seeing new ground conquered, previously unimaginable alliances being mooted and the risk of a devastating clash between two foes whose calculations had long been that shadow wars through proxies were safer than facing up directly.

The shift in approach has been led from Riyadh, where a new regime determined to put Saudi Arabia on an entirely different footing domestically, is also trying to overhaul how the kingdom projects itself regionally – and globally.

The ambitious, unusually powerful, crown prince, Mohammed bin Salman, has been given a mandate by his father, King Salman, to take on what the kingdom and its allies in the United Arab Emirates see as an Iranian takeover of essential corners of the Sunni Arab world.

By forcing Hariri to resign, the Saudis may be deliberately trying to start a civil war in Lebanon. The ostensible reason for pulling support from Hariri was that he wasn't tough enough with Hezb'allah. Hariri tried to argue - in vain - that his position in Lebanon was extremely delicate and that trying to stand up to Hezb'allah would destabilize the country. That the Saudis ignored this warning was not lost on Lebanese factions. Sunni, Shiite, and Christians in Lebanon are preparing for the unthinkable - a repeat of the civil war that devastated the country for 20 years. 

Lebanon may be the focus of the conflict today, but the civil war in Yemen is actually far more of a threat to Saudi Arabia than anything that happens in Lebanon. Iranians are using their Houthi allies to bleed Saudi Arabia, forcing the Kingdom to devote more and more militiary resources to a conflict that is apparently without end. Thanks to the return to Iran of frozen assets by the Obama administration following the nuclear deal, Iran has nearly unlimited funds to pour into Yemen and directly threaten the Saudis.

At this point, it wouldn't take much to ignite a shooting war between the Saudis and Iran. The Kingdom has already warned Iran that missiles from Yemen will be considered an attack by Iran and a push by Hezb'allah to engineer a complete takeover of Lebanon might also be seen as an act of war. 

Can the two sides pull back from the brink? Not with the stakes as high as they are and the belief by both sides that their enemy represents and existential threat to their existence.