Ukraine war latest: Russian port suffers 'massive' overnight attack and oil refinery left in flames - as Putin's forces advance

As the situation around Kharkiv remains "highly dramatic", Germany's foreign minister says Ukraine needs more long-range weapons to cut off Russian supply routes.

While Volodymyr Zelenskyy says the situation has "stabilised" (see our 9.04am post), Russian troops have advanced as much as 10km in one area.

This has put added pressure on Ukraine's already-stretched forces.

Speaking on the sidelines of a meeting of foreign ministers in Strasbourg, Annalena Baerbock said it is important to provide weapons "that can be used over medium and long distances".

"We are also working with other partners on this," she said, adding it is overall an "extremely difficult situation".

Germany has become Ukraine's second-biggest supplier of weapons, but Chancellor Olaf Scholz has so far balked at delivering long-range Taurus missiles.

The West has generally prohibited the use of its weapons on Russian territory, but Moscow claims some of those arms have been used within the country's borders.

Kyiv is preparing troops to defend the northern region of Sumy, according to the commander-in-chief of Ukraine's armed forces.

Oleksandr Syrskyi says he expects fighting to intensify as Russia continues to attack Kharkiv - with Sumy the next possible target, roughly 170km northwest.

Russia's attack on Kharkiv has expanded the area of active fighting by almost 70km, he added, which was designed to force Ukraine to divert stretched resources to the region.

Vladimir Putin in the northern province of Harbin today as part of his official visit to China.

Today, he's said Russia's strategic alliance with China in the energy sector will strengthen further - adding Moscow is ready to supply clean energy to its neighbour.

Speaking at a Russia-China Expo, Mr Putin said the close relationship between the two countries is a guarantor of energy security.

Here are some of the first pictures coming out of his second day of the trip.

Ukraine's military claims it has shot down all 20 drones it says Russia dispatched overnight to Kharkiv, Poltava, Vinnytsia, Odesa and Mykolaiv.

As we reported earlier, Kharkiv sounded its longest air raid alert since the invasion began (see our 6.37am post).

The region of Kharkiv has been increasingly targeted this spring, with Russia intensifying aerial attacks and mounting a new offensive in the border areas, forcing Kyiv's outnumbered troops to try to hold the line on a new front.

The attack damaged five buildings, one of them belonging to the district administration, Kharkiv's regional governor, Oleh Syniehubov, said on Telegram.

Kharkiv city mayor Ihor Terekhov reported four explosions during the attack, adding one of the strikes caused a fire.

Three drones were shot down over the Poltava region with no casualties or infrastructure damages, according to its regional governor, Filip Pronin.

Also on Telegram, Mykolaiv's regional governor, Vitaliy Kim, said there had been no casualties after the overnight attacks.

Volodymyr Zelenskyy says the situation in Kharkiv has "stabilised" as of today, as cited by news outlet RBC-Ukraine.

He says Russian forces have advanced 10km (6 miles) in one area of the region, which has been intensely targeted by Moscow in a bid to stretch Ukraine's already-outnumbered troops.

“Today, our defence forces have stabilised the Russians where they are now," he said. 

"The deepest point of their advance is 10 km."

Later, he posted on X "we must use all available means to force Russia to make a real and just peace", adding the country's defence is "critical" for this.

We have reported this morning Russia claimed a Ukrainian drone attack caused a fire at an oil refinery in Krasnodar (see our 6.44am post).

Footage shared by The Wall Street Journal's chief foreign affairs correspondent, Yarsolav Trofimov, shows a fire at the Tuapse refinery.

The attacks may have been more successful than Russia lets on, with another video showing burning fuel depots at the Novorossiysk railway, also in Krasnodar.

The Russian defence ministry said air defences downed 51 Ukrainian drones over Crimea, another 44 over the Krasnodar region and six over the Belgorod region. 

Russian warplanes and patrol boats also destroyed six sea drones in the Black Sea, the ministry added.

Kim Yo Jong, the influential sister of North Korean leader Kim Jong Un, has again denied reports of arms exchanges with Russia - insisting the country's updated weapons systems are not for sale.

According to state-run KCNA, Kim Yo Jong said North Korea's recently-shown tactical weapons, such as rocket launchers and missiles, are for defence against South Korea, with the two countries technically still at war since their 1950-53 conflict ended in a truce, not a treaty.

The US and South Korea have accused North Korea of transferring weapons to Russia for its war in Ukraine.

Despite vowing to deepen military relations last year, both Moscow and Pyongyang have denied the accusations.

While ties between the two countries have strengthened dramatically in recent months, Kim Yo Jong said the North Korea-Russia arms deal "theory" made up of prejudice and fiction was the "most absurd theory", according to KCNA quoting her press statement.

She called it a false rumour spread by its hostile forces.

A Russian official claims a Ukrainian drone strike killed a mother and her four-year-old son in the southern region of Belgorod.

Vyacheslav Gladkov, the regional governor, says the pair were traveling in a car earlier today when one of several drones opened fire in the village of Oktyabrsky.

The woman died at the scene, while the boy died of his injuries at hospital.

The boy's father and a man driving the car were injured, but survived.

New satellite imagery appears to show damage at Belbek airbase in Russian-annexed Crimea.

Among the apparent targets were a fuel storage facility and several types of fighter jet.

Officials in Russia's Krasnodar region reported another Ukrainian drone attack on an oil refinery, this time causing a fire.

So far, no casualties have been reported at Tuapse oil refinery and authorities say they have contained the fire.

Meanwhile, Russia's defence ministry claims its air defence and the Black Sea fleet destroyed 102 Ukrainian drones and six unmanned boats overnight.

As a result of that attack, the governor of Sevastopol, in annexed Crimea, says an electrical substation was damaged.

"There will be isolated blackouts," he wrote on messaging app Telegram.

He says he has cancelled classes "in all schools, institutions of secondary vocational education and kindergartens".