It could be a punitive action, says Huovinen, who works at the Finnish National Defence University.
Previously, Russian attacks almost always occurred at night. Now they also occur during the day.
"In the last week or two, there has been an increased number of attacks with drones, aircraft and ballistic missiles," he says.
Some of the Good Friday daylight attacks, which claimed several civilian lives, were carried out, according to Kyiv, with glide bombs dropped by Russian attack aircraft.
Can't get to them
According to Huovinen, Russia can drop the glide bombs from several miles away. The fact that such attacks are now taking place during the day may be because Russia feels that the Ukrainians cannot fight them at that distance.
"You can't afford to have that type of air defense so close to the front, but you use them to protect important cities," says Huovinen.
And the portable anti-aircraft missile systems don't have that range. They can't reach them. Then Russia can carry out bombings day and night.
Ukraine's air defense consists of several systems from several countries - not least the United States. Among them is the much-talked-about Patriot system.
Resources are being used up in Iran
Johan Norberg, a security policy analyst at the Swedish National Defense Research Institute (FOI), says that the US and its allies have burned large amounts of air defense resources in the war against Iran, including Patriot missiles.
The concern in Ukraine now is that the demand for Patriot missiles will increase further; there were already long queues to buy them, says Norberg.
This could have an impact on Ukraine in the future.
I think there will be tougher competition for existing resources.
Johan Huovinen is of the same opinion about the Patriot missiles, which Ukraine is already using.
It's more of a concern for the future than right now, he says.
