Abu Dhabi, federal capital of the United Arab Emirates, was this week hit by a drone attack claimed by Iran-backed Houthi rebels in Yemen. The assault risks ending the first serious attempts in decades to build detente across the Gulf between the Sunni Arab monarchies and Iran’s Shia Islamic republic. It has set nerves jangling and shows how Yemen is starting to resemble Syria as a conflict able to radiate mayhem beyond its borders.

It rivals in boldness the 2019 drone and missile attack on Aramco oil installations in Saudi Arabia — a devastatingly accurate double strike also claimed by the Houthis but almost certainly carried out by Iran — that briefly took out half the crude output of the world’s top oil exporter.

The difference here is that whoever did the UAE strike was aiming off: a shot across the bows.

The heterodox Shia Houthi movement that now controls most of north Yemen, including the capital, Sana’a, was in a state of revolt long before it helped overthrow Yemeni strongman Ali Abdullah Saleh in 2012. After a Saudi-led coalition including the UAE went to war against the Houthis in 2015, Iran and its proxies, such as Lebanon’s Hizbollah, seized the opportunity to back them as leverage against Saudi Arabia, its rival for regional hegemony.

After the 2019 attack on Aramco, and the failure of the US under then president Donald Trump to respond, the UAE largely withdrew from Yemen and declared it would be concentrating on expanding its thriving economy, based on trade and tourism — and stability. That took a hit with this week’s exposure of its vulnerability.

But, unlike then, these were warning shots: near Abu Dhabi international airport and near an oil storage facility of Adnoc, the state oil company. These strikes were so precise that analysts and officials in and outside the UAE are wondering whether Iran was behind them, rather than Houthi militiamen.

The warning to the UAE was not to re-enter the Yemen war. This month, UAEbacked forces halted a string of Houthi advances by retaking Shabwa province and relieving the pressure on oil-rich Marib, the last government foothold in the north that the rebels came close to overrunning.