For the first time, Israel has struck inside Yemen, following a deadly drone attack launched by Houthi rebels on Tel Aviv.

Since the October 7 attacks by Hamas on Israel, the Houthis have been targeting shipping in the Red Sea in solidarity – they say – with Gaza. But these direct attacks on each other’s soil between the Israeli military and an Iranian-backed rebel group risk creating a new front in a conflict that already threatened to spill over into the region.

Soon after the Israeli attack, the Houthis said they launched a fresh barrage of missiles towards Israel, promising a response that will be “huge and great.”

Here’s what we know.

Who are the Houthis and what is their role in the Gaza conflict?

The Houthis are an Iran-backed Islamist group based in Yemen.

The Houthi movement, also known as Ansar Allah (Supporters of God), is one side in a civil war that has raged in Yemen for nearly a decade. It emerged in the 1990s, when its leader, Hussein al-Houthi, launched “Believing Youth,” a religious revival movement for a centuries-old subsect of Shia Islam called Zaidism.

Since a ceasefire, the Houthis have consolidated their control over most of northern Yemen. They have also sought an agreement with Saudi Arabia, a major rival of Iran, that would bring the war to a permanent end and cement their role as the country’s rulers.

The Houthis are believed to have been armed and trained by Iran. Since Hamas’s attacks on October 7 attacks and Israel’s subsequent ground and air offenses in Gaza, the Houthis say they have been seeking revenge against Israel for its military campaign by targeting Red Sea shipping.

The US and UK have responded to those attacks by carrying out strikes on Houthi targets in Yemen. However, Israel has not taken part in those responses.

In addition, Israel’s army spokesman says the militant group has targeted “Israeli civilians and civilian infrastructure” about 200 times in the same period. Most of those launches were intercepted by US Central Command, the spokesman said, but Israel’s air defenses have also intercepted Houthi drones and missiles inside and outside Israel’s airspace.

What happened in Tel Aviv?

A tipping point for Israel appears to have come on Friday, when a drone attack was launched on Tel Aviv, killing one Israeli citizen and injuring several others.

The attack was claimed by the Houthis, with spokesperson Yahya Sare’e saying the operation was performed by a new drone capable of “bypassing the enemy’s interception systems.”

“We will continue to strike these targets in response to the enemy’s massacres and daily crimes against our brothers in the Gaza Strip,” Sare’e said. “Our operations will only cease when the aggression stops and the siege on the Palestinian people in the Gaza Strip is lifted.”

The attack marked the first time Tel Aviv, Israel’s commercial center, has been struck by a drone in an attack claimed by the Houthis. Israel authorities are investigating the circumstances and potential security failures around the deadly drone blast.

Israel Defense Forces (IDF) spokesman Daniel Hagari said that the military suspects the drone was an Iranian-made Samad-3 model, launched from Yemen, which had been upgraded to extend its range.

A second drone was intercepted outside of Israeli airspace to the east at the same time as the attack, he said, adding that Israel is now upgrading its air defenses and increasing aerial patrols of its borders.

How did Israel respond?

Israel’s response came a day later, when Israeli aircraft hit the Yemeni port of Hodeidah.

The attack, which marked the first time Israel has struck Yemen, killed at least six people and injured scores more, Yemeni officials said. The Houthi-run Al Masirah TV said the strikes targeted oil facilities in the port on Yemen’s west coast.

Houthi spokesperson Mohammed Abdulsalam said the strikes had also hit civilian targets and a power station. He slammed what he said was “brutal Israeli aggression” aimed at increasing the “suffering of the people of Yemen” and pressuring the group to stop its support of Gaza.

Israel’s Prime Minister Benjamin Netanyahu said the port was used by Iran to bring arms into Yemen.

“The port we attacked is not an innocent port. It was used for military purposes, it was used as an entry point for deadly weapons supplied to the Houthis by Iran,” he said in a statement on Saturday.

Netanyahu also said the operation, which hit targets 1,800 km (1,118 miles) from Israel’s borders, showed Israel was serious about responding to threats.

“It makes it clear to our enemies that there is no place that the long arm of the State of Israel will not reach,” Netanyahu said.

How big an escalation is this?

Neither side have suggested they are ready to back down. “It’s not in the Houthi ‘DNA’ to de-escalate with Israel,” Charles Lister of the Middle East Institute wrote on X.

Houthi army spokesperson Yehya Saree said the Houthis have “prepared for a long war” with Israel and that Tel Aviv is still not safe. Israel’s Defense Minister, Yoav Gallant, warned that the “blood of Israeli citizens has a price,” and that if Israelis are attacked, the “result will be identical” to that which has been seen in Lebanon and Gaza.

On Sunday, Israeli military said it had intercepted a missile approaching Israeli territory from Yemen while the Houthis said they launched a “number of ballistic missiles.”

The war in Gaza has already been accompanied by significantly heightened tensions between Israel and the Lebanese militant group Hezbollah. The two sides have been trading cross-border fire since October 8, when Hezbollah fired at three Israeli border posts “in solidarity” with Palestinians.

But while raised tensions with the Houthis undoubtedly creates fresh challenges for Israel, Hezbollah remains the bigger threat given its extensive arsenal and proximity to Israel.

He believes Israel was trying to send a signal to the US and the international community that “enough is enough,” and deliberately chose a target with high visibility.

“You have to signal to a rogue actor that is attacking you that there is a price to pay, and I think this is what Israel tried to do.”

Like the Houthis, Hezbollah is also heavily backed by Iran, which makes no secret of its animosity towards Israel.

Any increase in hostilities between Israel and Iran’s proxies is seen as deeply destabilizing in the region because it could push the two countries closer towards open warfare.

Israel and Iran have already traded one direct exchange since October 7. Few in the international community want to see it happen again.

This post appeared first on cnn.com