Two unprecedented attacks on Wednesday night, one by Iran and the other by Israel, shows the perennial enemies’ shadow war is coming out into the light. That threatens to turn the growing conflict into a full-blown war in the Middle East.

On Wednesday night, Iranian forces in Syria launched around 20 rockets into the Golan Heights, according to Israel’s military. Jerusalem blamed Iran’s Quds Force, an elite military unit responsible for external operations, for the attack.

The Israel Defense Forces said it intercepted four of the rockets and that “no hits were located in Israel” because the rest of the projectiles landed in Syria. No injuries were reported, but the missile strikes were a grim milestone all the same: They marked the first time Iran had ever directly targeted Israeli forces.

Israel hit back hard. Israeli forces attacked dozens of Quds Force positions in Syria in what was Jerusalem’s most extensive attacks in the country since at least 1973. Israel said it hit Iranian weapons storage facilities, logistics areas, and intelligence-gathering locations in Syria. If true, the strikes could significantly degrade Iran’s ability to operate in Syria, where it helps Bashar al-Assad stay in power — unless, as seems likely, Iran quickly rebuilds the sites.

The Israeli military put out a map showing where it dropped bombs, adding that Jerusalem “does not seek to escalate the situation.” The map goes to show just how much intelligence Israel has on Iran’s Syrian locations and its ability to seemingly penetrate Syrian air defenses at will to hit targets throughout the country.

The IDF has struck dozens of Iranian military targets in Syria in response to the Iranian rocket attack against Israel. Quds force is behind attack and has played the initial price. IDF remains ready for various scenarios but does not seek to escalate the situation. pic.twitter.com/4rC8gHK2LG — Jonathan Conricus (@LTCJonathan) May 10, 2018

On Thursday, Israeli Prime Minister Benjamin Netanyahu explained why his country responded the way it did. “Iran crossed a red line,” he said. “We responded accordingly.”

Israeli Defense Minister Avigdor Lieberman offered a warning to Iran soon after the retaliatory attack. It “must remember that if it rains here [in Israel], it will pour there,” he said at a conference in Israel. “I hope that we have finished this chapter and that everyone got the message.”

Iranian President Hassan Rouhani struck a different tone, noting Tehran didn’t want “new tensions” in the region.

In a statement, the White House said it “support[s] Israel’s right to act in self-defense.” A Pentagon spokesperson told me “the US had no involvement in these operations.” And, oddly, Bahrain supported Israel’s retaliation.

“As long as Iran continues the current status quo of its forces and rockets operating in the region, any country — including Israel — has the right to defend itself by eliminating the source of danger,” Khalid bin Ahmed al-Khalifa, Bahrain’s foreign minister, tweeted.

“This is an extremely dangerous situation”

Experts told me the Israel-Iran flare-up was years in the making.

“The cross-border strikes by both sides in the past 24 hours represent a dangerous, but not unsurprising, escalation,” says Shanna Kirschner, a Syria expert at Allegheny College.

Here’s why: Israel has struck Syria more than 100 times since the civil war started in 2011, in part because it’s worried about Tehran’s expanding military presence in the country. Iran has spent the past seven years using the Syrian civil war’s chaos to gain more control in the region. Israel doesn’t like that and uses military force to curb Iran’s influence.

“Iran is busy turning Syria into a base of military entrenchment,” Netanyahu said at a news conference last September. “It wants to use Syria and Lebanon as war fronts against its declared goal to eradicate Israel.”

“This is something Israel cannot accept,” he continued.

Israel escalated its attacks last month. On April 9, Israel killed around seven Iranian troops in Syria. Tehran threatened to retaliate the following day but kept relatively quiet.

Then on May 8 — the same day President Trump withdrew America from the Iran nuclear deal — Israel put itself on “high alert” in preparation for an Iranian attack. It appears that Wednesday’s rocket attack was partially in response to Israel’s April 9 strike, and it’s unclear if it had anything to do with Trump’s Iran deal decision.

It’s clear the Israel-Iran conflict has moved to a new phase. Neri Zilber described the first part of this fight for Vox:

This first phase of the Israel-Iran showdown in Syria was thus conducted largely in the shadows and followed a well-worn pattern: An explosion would take place someplace in Syria, with later reports confirming that the target was a weapons convoy, an arms depot, or senior Iranian or Hezbollah operatives.

But let’s not minimize what transpired: Israel and Iran have sharply escalated their attacks on each other. Experts tell me there’s a significant chance that this spirals out of control — and gets much, much worse.

“This is an extremely dangerous situation,” James Jeffrey, a Middle East security expert at the Washington Institute for Near East Policy think tank, told me.

For more on the global implications of Trump’s decision, listen to the latest episode of the Worldly podcast.

Correction: An earlier version of this story referred to the Golan Heights as part of northern Israel. Israel conquered the region in 1967 and annexed it in 1981, but the move wasn’t recognized by the international community.