The distinct lawnmower-like sound of Russia's attack drones woke residents across Ukraine's second-largest city at 12:30am.
Over the next nine minutes, there would be no pause.
The intense overnight assault killed at least six people and wounded 60 others, including children, Ukrainian authorities said.
Olena Khoruzheva raced to the hallway with her two children as soon as they heard the drones approaching.
They tried to get as far away as possible from the windows.
Her youngest son lay on the floor with his hands over his head.
"I was on top of him," the 41-year-old pharmacist told AFP.
"We heard it approaching, silence, and then we were thrown against the wall."
That was just the beginning.
Eleven sites were hit within minutes, including three residential buildings, according to Kharkiv's regional governor.
"There were more explosions, then we heard people shouting, 'Help! Help!' Ms Khoruzheva said.
Her 65-year-old neighbour was one of those killed in the attack.
Authorities say at least 17 Shahed-type drones were launched at the city, which lies just 30 kilometres from the Russian border.
The Osnovianskyi and Slobidskyi districts took direct hits.
As the 3.5-metre-long and 2.5-metre-wide drones came hurtling towards buildings, residents did not know whether to stay put or run out to the streets.
The barrage seemed never-ending.
"We were very scared because there were many, many of them [Shahed drones]," resident Olha Kravets said.
"We thought that this could happen, but we did not expect our house to be hit.
"As soon as it struck, we panicked, we didn't know what to do, where to go, because it was still flying."
In one five-storey building, fires broke out in 15 apartments, Kharkiv Mayor Ihor Terekhov said.
Private homes, playgrounds, public transport, and key infrastructure were also struck.
Several cars were damaged by debris.
Kharkiv Regional Governor Oleh Syniehubov warned that it appeared Russia was using a new high-altitude dive-bombing tactic.
He said the drones had significantly increased their altitude, flying high above targets then sharply dropping before impact.
"Russian forces have changed tactic — they're now launching drones at 4,000 to 5,000 metres," he wrote on Telegram.
The tactic made it increasingly difficult for Ukrainian air defences to respond.
Vitalii Holovin's apartment was destroyed.
His home was engulfed in smoke, leaving him with no choice but to flee, leaving behind all his belongings.
"I didn't have a chance to take any documents or money," he said.
"There was a fire. I felt the smoke, I got out … It was impossible to stay in smoke and look for something."
His neighbour saved a dog from another apartment.
"The dog got burnt," she said.
"We carried it from the fourth floor."
The devastating nine-minute drone strike left carnage in the streets.
Emergency crews, municipal workers and volunteers worked through the night to extinguish fires and rescue residents from burning homes.
Regions were left without gas, water and electricity.
Dozens of the injured were hospitalised, including a two-year-old girl and a 15-year-old boy, Mr Syniehubov said.
There are fears for the many people still trapped under rubble.
Kharkiv withstood Russia's full-scale advance in the early days of the war. However, it has since been a regular target of drone, missile and guided aerial bomb assaults.
"Every new day now brings new cowardly strikes from Russia, and almost every strike is demonstrative," Ukrainian President Volodymyr Zelenskyy said on Telegram.
"Russia deserves increased pressure."
There was no immediate comment from Russia on the overnight attacks.
The Kharkiv attack followed Russia this week carrying out its two biggest air assaults of the war so far.
It launched almost 500 drones on Monday and 315 drones and seven missiles overnight on Tuesday.
Ukraine's air force said Russia had fired 85 drones across Ukraine overnight, 40 of which were shot down.
The attacks are part of intensified bombardments that Moscow says are retaliatory measures for Kyiv's recent attacks in Russia.
ABC/wires
