Ukrainian lawmakers approved on Thursday an army mobilization bill that sparked anger after it was stripped of provisions allowing long-serving soldiers to be discharged, as Moscow pounded the country's energy facilities, destroying a power station in the Kyiv region.

Kyiv has struggled on the battlefield for months, weakened by desperately needed US military aid that is blocked in Congress and a shortage of men and ammunition.

Russia launched an aerial attack on five Ukrainian regions overnight and throughout Thursday morning, killing at least four people in the southern city of Mykolaiv, officials said.

The strikes also "destroyed" a key power station near Kyiv -- the main electricity supplier for the Kyiv, Zhytomyr, and Cherkasy regions, energy officials said.

Ukrainian President Volodymyr Zelensky urged the West not to "turn a blind eye" to Russia's aerial attacks and to provide more air defenses.

He was speaking during a visit to Lithuania, one of Kyiv's staunchest allies against Russia.

Zelensky also signed a 10-year security cooperation agreement with Lithuania's neighbor Latvia, the latest in several similar agreements -- which are not mutual defense pacts -- with NATO countries.

Back at home, the Ukrainian parliament, the Rada, adopted a mobilization bill that was opposed for months by many in a country increasingly exhausted by war.

Facing pressure from army officials, lawmakers had a day earlier scrapped a clause in the bill that would have allowed soldiers fighting for more than 36 months to return home.

Soldiers at the front told AFP on Wednesday they were in "shock" about the demobilization clause being ditched.

The bill, which needs to be signed into law by Zelensky, will strengthen punishments for draft dodgers and set out new procedures for troop call-ups.

Russia's invasion of Ukraine has dragged on for more than two years, with no end in sight to fighting despite much of the front being virtually frozen.

Power station destroyed 

 Zelensky said Moscow had fired more than 40 missiles and 40 drones at sites across Ukraine overnight, targeting "critical infrastructure".

In the Kyiv region, officials said a Russian strike destroyed a key power plant.

"Russian troops destroyed the Trypilska TPP (power station)," Ukraine's energy ministry said.

"All workers who were on shift during the shelling are alive," it added, saying the strike caused a fire.

State company Centrenergo, which operates the plant, said it was the "largest supplier of electricity in the Kyiv, Cherkasy and Zhytomyr regions."

"The scale of destruction is terrible. It can't be calculated in financial terms," Centrenergo chairman Andriy Hota said.

Built-in the 1960s, the plant became the main generating facility in the area following the shutdown of the Chornobyl nuclear power plant.

It was also a major employer for the city of Ukrainka, south of the capital.

The town's mayor had earlier advised locals to shut their windows while firefighters sought to extinguish the blaze at the plant.

"I ask everyone to close the windows in their homes tightly so as not to breathe in harmful combustion products," Oleksandr Turenko said.

Moscow said it had launched what it called "retaliatory strikes" on Ukraine's energy facilities after a spate of attacks by Kyiv's forces on Russian oil refineries.

  Four dead in Mykolaiv 

 Ukraine's southern command said at least four people were killed in an attack on Mykolaiv.

"They insidiously hit Mykolaiv in the middle of the day," it said.

"According to preliminary information, four civilians were killed, five were wounded."

The Ukrainian city of Kharkiv -- which is being pounded on an almost daily basis at present -- was also attacked again, a day after a strike killed three people there.

Ukrainian Interior Minister Igor Klymenko described a "massive" attack that lasted "for several hours".

 'No sense' 

 In Ukraine's westernmost region of Lviv, authorities said Russian troops attacked a gas distribution facility and an electricity substation.

Russia, meanwhile, said it had destroyed 12 Ukrainian drones overnight, including three as far east as its Mordovia republic, more than 500 kilometers (300 miles) from the border.

Others were destroyed over the Kursk, Tambov, Belgorod, Bryansk, and Lipetsk regions, it said.

Both countries have been firing dozens of drones at each other in waves of overnight attacks throughout the year, now in its third year.

In Moscow, the Kremlin criticized plans to hold a Ukrainian peace conference in Switzerland in June.

"We said many times that the process of (peace) talks without Russia makes no sense," Kremlin spokesman Dmitry Peskov told reporters.