KYIV, BRATISLAVA. A day after a drone attack on air bases in the Russian hinterland, the Ukrainian secret service reported another attack. This time on the Kerch Bridge, which connects the Russian mainland with the occupied Ukrainian peninsula of Crimea.

The explosion near one of the bridge's pillars occurred on Tuesday before 5 a.m. local time, the Kyiv Post newspaper reported, citing the SBU secret service, which also posted a video on social media showing the explosion near the bridge.

The SBU said the attack used explosives equivalent to 1,100 kilograms of trinitrotoluene and hit the pier at the seabed. Kiev said the explosion put the bridge out of service, but it was unclear for how long early Tuesday evening.

According to Kyiv Post, pro-Russian sources on the Telegram social network reported repeated interruptions and resumptions of road traffic on the bridge, and there were also mentions of a second explosion at around 3:30 p.m.

How many explosions occurred?

On Tuesday, the SBU reported, according to the Kyiv Independent, that the operation had been in preparation for several months, and referred to the explosion at 4:44 a.m. as the"activation of the first explosive device."

Pro-Russian sources on Telegram wrote on Tuesday about the shooting down of aerial drones over Crimea around 6 am, as well as the detention of an alleged Ukrainian agent. However, according to the BBC, Russia detained him near Sevastopol, a city on the opposite coast of Crimea from the Kerch Bridge.

The BBC was able to geolocate the location of the first explosion near the pillar supporting the road section of the bridge, while the periods during which the bridge was closed, opened and then closed again would indicate that a second explosion did indeed occur near it in the afternoon.

Although it was not clear what explosive the Ukrainian special forces used, the British station recalled that the United States has provided Ukraine with C-4 plastic explosive on several occasions.

Since Ukraine has previously attacked the bridge with water drones, Russia has placed protective barriers near it. Several pro-Russian sources also wrote on Tuesday that the explosions near the bridge were caused by Ukrainian surface drones hitting these barriers.

Message to allies

As an occupation artery, the Kerch Bridge is a legitimate military target, but attacks on it make sense even if Ukraine is unable to physically put it out of action.

"We don't want to show force, but we show it because the enemy doesn't want to stop. We show it fairly, towards military targets," CNN quoted Ukrainian President Volodymyr Zelensky as saying.

"We are not only showing it to the Russian aggressors, but also to all allies who were once strong allies but have begun to question us," he said.

Cedric Leighton, a military expert and former US Air Force colonel, also assessed the attack in a similar manner in an interview with an American station.

"This is not just a military campaign, it is also a PR campaign by Ukraine to win back its allies. To convince people in the US and Western Europe that Ukraine is worth fighting for," he said.

According to him, what is important is that Ukraine is able to carry out attacks on Russian targets, which seemingly contradicts what is happening on the front, where Russia has the upper hand and is slowly advancing.

"The Ukrainians rely on precision. It shows us that they are using intelligence very precisely, they are not using the Soviet method of mass attacks. This also means fewer casualties at civilian targets," Leighton believes.

The bridge has been attacked in the past

Russia began building the Kerch Bridge in 2016, and its construction, including the railway section, took three years.

It has since become an important transport artery, used by Russia even during the current phase of the war against Ukraine. Although its military importance has since declined, it remains a symbol of Russia's occupation of the peninsula, which has lasted since 2014.

Since 2022, when Russia unleashed the current phase of the war against Ukraine, the Kerch Bridge has been a legitimate target for Ukrainian troops.

A major attack occurred in October 2022, when a truck loaded with explosives exploded on the bridge. Two segments of the road (not rail) section of the bridge collapsed into the sea.

Technologically more interesting was the attack in July 2023, when Ukraine attacked the bridge using Sea Baby surface drones, each carrying 850 kilograms of explosives.

Ukraine also used the same drones in attacks on Russian warships in the Black Sea.