President Vladimir V. Putin of Russia ordered a far-reaching series of missile strikes against cities across Ukraine on Monday, hitting the heart of Kyiv, the capital, and other areas far from the front line in the broadest aerial assault against civilians and critical infrastructure since the early days of Moscow’s invasion.

Russia’s attacks killed at least 11 people nationwide and wounded 89 others, the Ukrainian authorities said and knocked out power and other key services in multiple cities.

Putin said the strikes were in response to a blast that hit a key Russian bridge over the weekend, which he called a “terrorist attack”. He threatened further strikes if Ukraine continued to hit Russian targets.

Dozens of missile strikes — from Lviv in the west to Mykolaiv in the south and Kharkiv in the northeast — slammed into civilian areas during the morning commute and apparently also sought to cripple energy facilities as winter approaches.

The explosions blew out the windows of buildings in central Kyiv, set vehicles ablaze and sent residents scrambling for shelter at a time when many were heading to school or work.

Experts said it was too soon to say whether the attacks against mainly civilian targets would have a significant impact on Ukraine’s military, but they appeared designed to placate Russian hard-liners who have been calling for Putin to intensify the war.

As Ukrainian troops have reclaimed more than 1,200 miles of territory in the east and south, Putin has faced mounting criticism of his army’s performance and growing opposition to his callup of hundreds of thousands of civilians into military service.

Putin vowed a “tough” and “proportionate” response should Ukraine carry out further attacks that threaten Russia’s security.

“No one should have any doubts about it,” he said.

Monday’s intense, hourslong attack by Russia marked a sudden military escalation in its assault on Ukraine.

It came a day after Putin called the explosion on Saturday on the huge bridge connecting Russia to its annexed territory of Crimea a “terrorist act” masterminded by Ukrainian special services.

Putin, speaking in a video call with members of Russia’s Security Council, said the Russian military launched “precision weapons” from the air, sea and ground to target key energy and military command facilities.

The missile strikes marked the biggest and most widespread Russian attacks in months.

Putin, whose partial mobilisation order earlier this month triggered an exodus of hundreds of thousands of men of fighting age from Russia, stopped short of declaring martial law or a counterterrorism operation as many had expected.

But the sustained barrage on major cities hit residential areas and critical infrastructure facilities alike, portending a major surge in the war amid a successful Ukrainian counteroffensive in recent weeks and raising questions about how “precise” Russia’s targeting is.

Moscow’s war in Ukraine is approaching its eight-month milestone, and the Kremlin has been reeling from humiliating battlefield setbacks in areas of eastern Ukraine it is trying to annex.

Blasts struck in the capital’s Shevchenko district, a large area in the centre of Kyiv that includes the historic old town as well as several government offices, mayor Vitali Klitschko said.

Some of the strikes hit near the government quarter in the symbolic heart of the capital, where the parliament and other major landmarks are located. A glass tower housing offices were significantly damaged, most of its blue-tinted windows blown out.

Residents were seen on the streets with blood on their clothes and hands. A young man wearing a blue jacket sat on the ground as a medic wrapped a bandage around his head.

A woman with bandages wrapped around her head had blood all over the front of her blouse.

Several cars were also damaged or completely destroyed.

Air raid sirens sounded repeatedly across the country and in Kyiv. Ukrainian President Volodymyr Zelenskyy said Russian forces launched dozens of missiles and Iranian-built drones against Ukraine.

The General Staff of the Ukraine Armed Forces said 75 missiles were fired against Ukrainian targets, with 41 of them neutralized by air defences.

The targets were civilian areas and energy facilities in 10 cities, Zelensky said in a video address.

“(The Russians) chose such a time and such targets on purpose to inflict the most damage,” Zelensky said.

The morning strikes sent Kyiv residents back into bomb shelters for the first time in months.

The city’s subway system stopped train services and made the stations available once more as places for refuge.

While air raid sirens have continued throughout the war in Ukraine’s major cities across the country, in Kyiv and other areas where there have been months of calm many Ukrainians had begun to ignore their warnings.

That changed on Monday morning.

The attacks arrived in Kyiv at the start of the morning rush hour, when commuter traffic was beginning to pick up.

At least one of the vehicles struck near the Kyiv National University appeared to be a commuter minibus, known as a “marshrutka” which is a popular albeit often crowded alternative to the city’s bus and metro routes.

Nearby, at least one strike landed in the popular Shevchenko Park, leaving a large hole near a children’s playground.

Among the targets hit was a pedestrian bridge known as the Klitschko bridge — a landmark in central Kyiv with its glass panels.

Closed-circuit television footage shared by an adviser to Ukraine’s interior minister showed a huge explosion as the bridge was apparently targeted.

A man seen on the bridge just before the explosion is seen running away after the blast. Lesia Vasylenko, a member of Ukraine’s parliament, tweeted a photo showing that at least one explosion occurred near the main building of the Kyiv National University in central Kyiv.

Elsewhere, Russia targeted civilian areas and energy infrastructure as air raid sirens sounded in every region of Ukraine, except Russia-annexed Crimea, for four straight hours. Associated Press journalists in Dnipro city saw the bodies of multiple people killed at an industrial site on the city’s outskirts.

Windows in the area had been blown out and glass littered the street.

A telecommunications building was hit. Ukrainian media also reported explosions in a number of other locations, including the western city of Lviv, which has been a refuge for many people fleeing the fighting in the east, as well as in Kharkiv, Ternopil, Khmelnytskyi, Zhytomyr and Kropyvnytskyi.

Kharkiv was hit three times, mayor Ihor Terekhov said.

The strikes knocked out the electricity and water supply.

Energy infrastructure was also hit in Lviv, regional governor Maksym Kozytskyi said.

A day earlier, Putin had called the attack on the Kerch Bridge to Crimea a terrorist act carried out by Ukrainian special services.

In a meeting on Sunday with the chairman of Russia’s Investigative Committee, Putin said “there’s no doubt it was a terrorist act directed at the destruction of critically important civilian infrastructure.”

Amid the onslaught, Zelensky said on his Telegram account that Russia is “trying to destroy us and wipe us off the face of the earth”.

New York Times News Service and AP/PTI