Russia launched a series of ballistic missile strikes on several cities in Ukraine on Saturday. At least four people were killed and more than 36 were injured in the attacks, Ukrainian officials said.

Three people were killed and 20 injured in the northeastern city of Kharkiv. One person was killed and 16 injured in the capital, Kiev.

Ukrainian President Volodymyr Zelensky said Saturday's attack was one of the largest ballistic missile strikes on Kiev since Russia launched a full-scale offensive in 2022. 

The Ukrainian military said missiles were fired at various parts of the Kiev region overnight.

The military also said that defense systems intercepted 18 of the 41 missiles fired by Russia in the air. Defense systems also downed 108 drones.

Meanwhile, Ukraine has continued its counterattacks on Russian territory. According to President Zelensky, Ukraine has targeted three Russian oil tankers on the Black Sea and various infrastructure in the southwestern Stavropol region.

According to the head of the Kharkiv region, Oleg Sinyhubov, Russia has attacked a postal terminal on the outskirts of the city. Three men have died in the incident. Three of the injured are said to be in serious condition.

Ukrainian President Zelensky said in a telegram that Russia has fired about 1,450 strike drones, more than 1,640 controlled bombs and 99 missiles of various types against Ukraine in the past week.

According to Zelensky, Ukraine has also intensified its counterattack. Ukraine has simultaneously attacked three oil depots in Russia's Stavropol region. Ukrainian forces have also damaged another energy infrastructure in the same region.  

Similarly, Russia  The Ukrainian Air Force said it used 125 drones, including hypersonic missiles such as Iskander and Zircon, in the latest attack on Kyiv.

Kyiv Mayor Vitali Klitschko said the attack damaged residential buildings, supermarkets, dormitories and various offices and industrial sites. 

A logistics hub in the Bucha district was also hit, injuring two people. 

The governor of Russia's Stavropol region confirmed that a fire had broken out in an industrial park as a result of the drone attack.

In addition, the Caspian Pipeline Consortium  has suspended oil loading operations after the attack on its terminal. However, the company said there were no casualties or oil spills.  

Earlier, Ukraine had carried out drone attacks targeting two warehouses of Russia's largest e-commerce platform, Wildberries. The attack killed eight people and caused a large fire.

The attack on a warehouse in the city of Kotovsk, about 475 kilometers southeast of Moscow, injured 25 people. According to regional governor Yevgeny Pervyshov, all of those killed were employees working the night shift. 

Ukrainian President Zelensky has acknowledged that Russia's critical infrastructure and services have been attacked.

"Ukraine has taken these actions in response to Russia's attacks on our civilian infrastructure, cities and communities," Zelensky said.

He said the long-range drone attack was on Russia's energy infrastructure. Ukrainian officials have claimed that the recent Ukrainian attacks have caused a fuel shortage in Russia. 

Ukraine has been asking its European partners to increase supplies of ballistic missile defense systems to deter the attack, as Russia has stepped up its attacks. 

Zelensky said of the current situation in Ukraine on Sunday, "Preventing damage from ballistic missiles is our top priority now." We need defense systems every day.’

Earlier, Zelensky said that a political agreement had been reached with the US on a license to produce Patriot interceptors and that production was expected to begin by the end of this year.

However, the recent escalation of Russian aggression has put pressure on Ukraine to urgently supply weapons and defense systems from its allies.

The war, which began when Russia invaded Ukraine in 2022, has killed a large number of people. Public infrastructure in both countries has also been severely damaged.