Ukrainian authorities ordered families with children to urgently evacuate the eastern city of Pokrovsk on Monday, as the Russian army advances rapidly despite a Ukrainian blitz into Russia's Kursk region.

Local authorities stated that Russian forces are advancing so quickly that families were ordered to leave the city and other nearby towns and villages starting Tuesday. Officials said about 53,000 people still live in Pokrovsk, and some have decided to leave immediately.

People of all ages boarded trains and buses carrying whatever luggage they could manage. Some cried as they waited to leave. Soldiers helped the elderly carry their bags, and volunteers assisted people with disabilities. Railway workers wore bulletproof vests.

Natalia Ivanuyk said the noise of explosions from Russian shelling filled the air as she and her two daughters, aged 7 and 9, fled their home in the nearby village of Myrnohrad, which is less than 10 kilometers (6 miles) from the front line.

She told the Associated Press, "It was very scary. We barely got out."

Pokrovsk is one of Ukraine's main defensive strongholds and a major logistics hub in the Donetsk region. Capturing it would jeopardize Ukraine's defensive capabilities and supply routes, bringing Russia closer to its stated goal of seizing the entire Donetsk region.

One of Kyiv's attempts to alleviate pressure on its eastern front was the unexpected incursion into Russia's Kursk region on August 6, which aimed, among other objectives, to instill concern in the Kremlin and force it to divide its military resources.

Ukrainian President Volodymyr Zelensky said on Sunday that the bold incursion aims to create a buffer zone that could prevent further attacks from Moscow across the border, especially by long-range artillery, missiles, and glide bombs. This operation continued on Monday in complete secrecy.

Russia has spent six months of hard work across the Ukrainian Donetsk region since seizing Avdiivka, significantly bolstering its forces and armored vehicles. However, the attack is gradually reaping its rewards as Ukrainian defenders have no choice but to withdraw from positions destroyed by Russian artillery, missiles, and bombs.

Tetyana Mironinenko, 57, who came from Selydove just five kilometers (3 miles) from the front line, said, "There's so much destruction around us, so staying becomes more and more frightening."

She sat beside her husband on a train waiting to leave Pokrovsk. It was headed to Lviv, hundreds of kilometers (miles) to the west in Ukraine.

Russia aims to control all parts of neighboring Donetsk and Luhansk, which together form the industrial Donbas region.

Officials warned last week that Russian forces are advancing rapidly and are only 10 kilometers (6 miles) from the outskirts of Pokrovsk.

General Oleksandr Syrskyi, Ukraine's chief commander, said on Monday that "intense fighting" is taking place in the Pokrovsk area.

The nearby town of Toretsk, whose capture would open the door for a Russian advance on the main stronghold of Chasiv Yar from the south, is also under rebel control. He stated, "The pressure is intense."

The Institute for the Study of War reported that Russian forces have been advancing approximately two square kilometers (0.8 square miles) daily in the Pokrovsk area over the past six months.

The Washington-based Institute for the Study of War reported late Sunday that they have relied on frontal infantry attacks from village to village, making gradual progress while demonstrating their superiority in manpower and materials.

Pokrovsk officials have been meeting with residents to provide logistical details about the evacuation. People have been offered shelter in western Ukraine, where they will be hosted in prepared accommodations and separate houses.

In other developments:

Regional head Denis Pushilin stated on social media that a pregnant woman was killed and 10 others were injured in Ukrainian shelling in the Russian-occupied city of Donetsk. He noted that two children were among the injured.

In the Russian city of Proletarsk, about 270 kilometers (170 miles) from the Ukrainian border, 41 firefighters needed medical attention, with 18 of them hospitalized due to a fire in a warehouse that started as a result of debris from an intercepted drone, according to regional governor Vasily Golubev.