According to Governor Vyacheslav Gladkov, more than 20 villages in Russia's Belgorod region - stretching 150 km along the Ukrainian border - have been hit by continuous attacks. However, according to CNN, the Ukrainian military has not officially recognized the operation.
The move is seen as Kiev's response to recent losses in Russia's Kursk region, which it controlled more than 1,000 square kilometres in August last year. However, in recent weeks, Russia has forced Ukraine to withdraw its troops from Kursk.
Both Russia and Ukraine are seeking an advantage on the 1,000-km front line as the weather is more favorable - in the context of the US government pushing for a ceasefire.
In his speech on the evening of March 29, Ukrainian President Volodymyr Zelensky called for a strong US response after a series of Russian airstrikes on Dnipro, Kryvyi Rih and many other areas.
We are waiting for a response - a serious response, Zelensky stressed, referring to 172 Russian drone attacks on Ukrainian infrastructure on the night of March 28. Only pressure can force Russia to negotiate peace.
It is unclear whether Ukraine's real goals in Belgorod - whether they intend to occupy the territory or just to reduce pressure on the battlefield of Kursk and neighboring Sumy province.
Ukrainian military commander Oleksandr Syrskyi said Russia was trying to penetrate Ukraine's Sumy region, while the Russian Defense Ministry said it had taken control of a small settlement there.
Compared to the Kursk operation last year, this attack in Belgorod is smaller in scale. According to Russian officials, Ukraine began cross-border attacks nearly two weeks ago. Some unofficial sources said that the Ukrainian army has advanced several kilometers into Russian territory, gaining a foothold in the village of Popovka and is still fighting fiercely.
Meanwhile, across the front, the Ukrainian army is facing many challenges. In eastern Ukraine, Russia continues to increase pressure in Pokrovsk and Donetsk, with the highest intensity since the beginning of the year.
On the southern front, the situation in Zaporizhzhia has also deteriorated. According to Ukrainian military spokesman Vladyslav Voloshyn, the number of Russian attacks here has increased significantly.
Video from the ground shows Russian forces advancing into the town of Shcherbaky. The Russian Defense Ministry announced it had taken control of the town on March 29. Some Russian sources said the fighting was still fierce.
According to Ukrainian military analyst Kostiantyn Mashovets, Russia has concentrated about 70,000 troops along with hundreds of tanks and artillery in the Zaporizhzhia front, which has been annexed by Russia.
