CNN
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The Middle East is moving ever closer to a full-scale regional war as Israel vowed to respond to the massive barrage of ballistic missiles Iran fired into the country on Tuesday night, capping a day of dramatic military escalation in the region.

“Iran made a big mistake tonight – and it will pay for it,” Israeli Prime Minister Benjamin Netanyahu said hours after the unprecedented attack.

Iran fired a volley of about 200 ballistic missiles at Israeli military targets, the largest attack of its kind to date, blaring sirens across Israel and activating the country’s sophisticated defense systems.

Iran’s leaders said the attack was intended as a warning to Israel not to enter into a direct war with its long-time enemy and that any Israeli response to the barrage would be met with “stronger and more painful” strikes.

The escalation came about 24 hours after Israel launched a ground war in Lebanon against Hezbollah, a powerful militant group backed by Iran, and days after Israel killed its leader Hassan Nasrallah in an attack on Beirut.

Here’s what we know.

Tuesday’s attack further changed the dynamics of the conflict, evolving from a war with Iran’s proxies to a direct confrontation between two regional military powers.

It is the second time that Iran has launched an airstrike on Israel this year, but Tuesday’s shelling was on a different scale.

In April, Iran launched an unprecedented large-scale drone and missile attack on Israel – the first direct attack of its kind on the country from its soil – in retaliation for a suspected Israeli attack on an Iranian diplomatic complex in Syria.

Iran announced this attack 72 hours in advance. It was widely believed that the attack was aimed at minimizing casualties while maximizing spectacle, as almost all of the 300 projectiles were shot out of the sky by Israel’s defense systems.

Israel responded a week later with a limited attack on Iran.

This time, Israel learned of the imminent threat just hours before Tehran launched the attacks. The targets included the headquarters of Israel’s Mossad intelligence agency in Tel Aviv, Israel’s second largest city, and the Nevatim and Tel Nof air bases.

Pentagon spokesman Maj. Gen. Pat Ryder said Tuesday’s Iranian attack was twice the size of the attack in April. This also included many other ballistic missiles that are harder to shoot and pose a real threat to Israeli citizens – many of whom were evacuated to shelters during the attack.

While the Israeli military said most of the rockets were intercepted, some landed on Israeli soil and appeared to cause damage. The shock waves caused by the attack also damaged homes in central Israel, according to the country’s authorities.

So far, diplomacy has failed to negotiate a deal between Israel and Hezbollah, and ceasefire and hostage negotiations between Hamas and Israel have failed.

Until a few weeks ago, some senior US officials privately believed that Washington’s diplomatic and deterrence efforts had helped successfully thwart a large-scale Iranian attack on Israel, sources told CNN.

“I think Nasrallah was the final straw,” said Jonathan Panikoff, a former senior intelligence analyst who specialized in the region.

With no way out and Israel seemingly unwilling to compromise with its regional enemies, Tuesday’s attack is perhaps the clearest sign that a much-feared regional war may soon ignite.

Meanwhile, both Israel and the US downplayed the effectiveness of the attack. Israel said the attack “failed.”

In almost a year of war, increasing escalations have repeatedly brought the region to the brink of a full-scale conflict.

In recent days, Israel’s ground invasion of southern Lebanon has opened a whole new front and increased attacks against other Iran-backed militants, including strikes against the Houthis in Yemen.

Israel eliminated Hezbollah’s leadership through a series of attacks and massive airstrikes across Lebanon that targeted the group’s infrastructure and capabilities but also killed more than 1,000 people, displaced about 1 million and destroyed homes and neighborhoods.

In Gaza, Israel’s war against Hamas continues almost a year after the Palestinian militant group attacked Israel. The ensuing war has killed more than 41,000 people, sparked a catastrophic humanitarian crisis and left much of the enclave in ruins.

Hamas, Hezbollah and the Houthis are all part of an Iran-led alliance that spans Yemen, Syria, Gaza and Iraq and has been attacking Israel and its allies since the war began. They say they will not stop attacking Israel and its allies until a ceasefire is reached in Gaza.

Iran has sought to characterize its attack as a balanced response to repeated escalations by Israel.

Iran’s Islamic Revolutionary Guard Corps said Tuesday’s rocket attacks focused on Israeli security and military targets and were in response to Israel’s killing of Nasrallah and other commanders, including Hamas politician Ismail Haniyeh, in the Iranian capital Tehran in July.

After the assassination of Hamas’s most important figure after the inauguration of Iran’s new president, the world held its breath to see how Tehran would react.

For months there was no response and tensions appeared to ease in the face of the serious consequences of an all-out war in the Middle East.

But Israel’s attacks and the escalating war in Lebanon have quickly changed that equation.

On Saturday, Netanyahu gave a fiery speech aimed at Iran, saying that Israel was “changing the balance of power in the region” and that “there is no place in Iran or the Middle East that the long arm of Israel will not reach.” .

Nasrallah’s death was necessary, he said, to return thousands of residents displaced by Hezbollah rocket attacks to their homes along the border with Lebanon and to prevent the group from launching a large-scale attack on Israel.

U.S. officials have long believed that both Iran and Hezbollah’s senior leadership wanted to avoid an all-out war with Israel, even if there was a shootout.

A major fear for U.S. and Arab diplomats is the possibility that Israel will strike inside Iran, possibly against its nuclear facilities. Former Israeli Prime Minister Naftali Bennett called on Israel to retaliate by destroying its nuclear program.

But Iran has made it clear that any response from Israel would lead to further escalation. Iranian President Masoud Pezeshkian said Tuesday’s operation was “only part of our power.”

And Hezbollah itself remains a dangerous opponent for Israel, as it has an arsenal of military assets that it could bring to bear.

The United States, Israel’s closest ally and largest arms supplier, said it would coordinate with Israel in its response to the attack. State Department spokesman Matthew Miller assured that there would be consequences.

U.S. Navy destroyers have fired interceptors against the Iranian missiles, and in recent weeks the U.S. has deployed more troops and warships to the region.

Since the start of Israel’s war in Gaza, US troops have also been the target of escalating attacks by Iranian-backed proxy groups. In January, a drone strike on a small U.S. outpost in Jordan killed three U.S. Army soldiers and injured more than 30 soldiers.

During this time, the United States has repeatedly stood steadfastly at Israel’s side. Defense Secretary Lloyd Austin said the U.S. will “never hesitate” to protect U.S. forces and its interests in the Middle East and that the U.S. remains ready and “poised” to defend its own forces and Israel.