BEIRUT (AP) -- Chris Knayzeh was in a town overlooking Lebanon's capital when he heard the rumbling aftershock of the 2020 Beirut port blast. Hundreds of tons of haphazardly stored ammonium nitrates had exploded, killing and injuring thousands of people.

Already struggling with the country's economic collapse, the sight of the gigantic mushroom cloud unleashed by the blast was the last straw. Like many other Lebanese, he quit his job and booked a one-way ticket out of Lebanon.

Knayzeh was in Lebanon visiting when news broke Tuesday that hundreds of handheld pagers had exploded across the country, killing 12, injuring thousands and setting off fires. Israel, local news reports said, was targeting the devices of the militant Hezbollah group. Stuck in Beirut traffic, Knayzeh started panicking that drivers around him could potentially be carrying devices that would explode.

Within minutes, hospitals were flooded with patients, bringing back painful reminders of the port blast four years ago that killed more than 200 people and injured more than 6,000, leaving enduring mental and psychological scars for those who lived through it.

In total, the explosions of pagers and walkie-talkies over two days killed at least 37 people and injured more than 3,000. Israel is widely believed to be behind the blasts, although it has neither confirmed nor denied responsibility.

"The country's state is unreal," Knayzeh told The Associated Press.

The port blast was one of the biggest non-nuclear explosions ever recorded, and it came on top of a historic economic meltdown, financial collapse and a feeling of helplessness after nationwide protests against corruption that failed to achieve their goals. It compounded years of crises that have upended the lives of people in this small country.

Four years after the port catastrophe, an investigation has run aground. The ravaged Mediterranean port remains untouched, its towering silos standing broken and shredded as a symbol of a country in ruins. Political divisions and paralysis have left the country without a president or functioning government for more than two years. Poverty is on the rise.

On top of that and in parallel with Israel's war in Gaza, Lebanon has been on the brink of all-out war with Israel for the past year, with Israel and Hezbollah trading fire and Israeli warplanes breaking the sound barrier over Beirut almost daily, terrorizing people in their homes and offices.

"I can't believe this is happening again. How many more disasters must we endure?" said Jocelyn Hallak, a mother of three, two of whom now work abroad and the third headed out after graduation next year. "All this pain, when will it end?"

A full-blown war with Israel could be devastating for Lebanon. The country's crisis-battered health care system had been preparing for the possibility of conflict with Israel even before hospitals became inundated with the wounded from the latest explosions, many of them in critical condition and requiring extended hospital stays.

Still, Knayzeh, now a lecturer at a university in France, can't stay away. He returns regularly to see his girlfriend and family. He flinches whenever he hears construction work and other sudden loud sounds. When in France, surrounded by normalcy, he agonizes over family at home while following the ongoing clashes from afar.

"It's the attachment to our country I guess, or at the very least attachment to our loved ones who couldn't leave with us," he said.

This summer, tens of thousands of Lebanese expatriates came to visit family and friends despite the tensions. Their remittances and money they spend during the holidays help keep the country afloat and in some cases are the main source of income for families. Many, however, cut their vacations short in chaotic airport scenes, fearing major escalation after the dual assassinations of Hezbollah and Hamas commanders in Beirut and Tehran last month, blamed on Israel.

Even in a country that has vaulted from one crisis to another for decades, the level of confusion, insecurity and anger is reaching new heights. Many thought the port blast was the most surreal and frightening thing they would ever experience -- until thousands of pagers exploded in people's hands and pockets across the country this week.

''I saw horrific things that day," said Mohammad al-Mousawi, who was running an errand in Beirut's southern suburb, where Hezbollah has a strong presence, when the pagers began blowing up.

"Suddenly, we started seeing scooters whizzing by carrying defaced men, some without fingers, some with their guts spilling out. Then the ambulances started coming."

It reminded him of the 2020 port blast, he said. "The number of injuries and ambulances was unbelievable. "

"One more horror shaping our collective existence," wrote Maha Yahya, the Beirut-based director of the Malcolm H. Kerr Carnegie Middle East Center.

"The shock, the disarray, the trauma is reminiscent of Beirut after the port explosion. Only this time it was not limited to a city but spread across the country," she said in a social media post.

In the aftermath of the exploding pagers, fear and paranoia has taken hold. Parents kept their children away from schools and universities, fearing more exploding devices. Organizations including the Lebanese civil defense advised personnel to switch off their devices and remove all batteries until further notice. One woman said she disconnected her baby monitor and other household appliances.

Lebanon's civil aviation authorities have banned the transporting of pagers and walkie-talkies on all airplanes departing from Beirut's Rafik Hariri International Airport "until further notice." Some residents were sleeping with their phones in another room.

In the southern city of Tyre, ahead of a speech by Hezbollah leader Hassan Nasrallah, city resident Hassan Hajo acknowledged feeling "a bit depressed" after the pager blasts, a major security breach for a secretive organization like Hezbollah. He was hoping to get a boost from Nasrallah's speech. "We have been through worse before and we got through it," he said.

In his speech, Nasrallah vowed to retaliate against Israel for the attacks on devices, while Israel and Hezbollah traded heavy fire across the border. Israel stepped up warnings of a potential larger military operation targeting the group.

Another resident, Marwan Mahfouz, said Israeli Prime Minister Benjamin Netanyahu has been threatening Lebanon with war for the past year and he should just do it.

"If we are going to die, we'll die. We are already dying. We are already dead," he said.

___

Karam reported from London. Associated Press writer Hassan Ammar contributed to this report.