By Anastasiia Malenko and Max Hunder

KYIV (Reuters) -Russia killed two people in an airstrike on the central Ukrainian city of Poltava on Thursday and damaged a military draft office there in what Kyiv said was a concerted campaign to disrupt recruitment for its war effort.

The strike on Poltava, which also injured 47 people and caused a fire at the city's main draft office, followed a drone attack on Monday near a recruitment centre in Kryvyi Rih. Both cities are regional capitals.

"We understand that their (Russian) goal is to disrupt the mobilisation process," Vitaliy Sarantsev, a spokesperson for Ukraine's ground forces, told Ukraine's public broadcaster.

"But I want to say that...it is too early (for Russia) to uncork the champagne because the process is impossible to stop."

Ukraine has struggled to fend off a bigger and better-equipped Russian army, and its call-up process has been marred by reports of draft-office corruption, poor training and weak battlefield command.

Well into the fourth year of its full-scale invasion, Russia has gained ground in eastern Ukraine and repeatedly hit cities far behind the front lines with drones and missiles, while also waging a sabotage campaign there, Kyiv's domestic security agency says.

In a statement to Reuters last month, the Security Service of Ukraine said it had arrested more than 700 people since 2024 for alleged crimes that included arson attacks on troop vehicles and bombings at draft offices.

A Ukrainian security official, who requested anonymity to discuss sensitive matters, said Russia was aiming to derail Kyiv's military call-up effort also by spreading disinformation and hacking recruitment office computers.

"The disruption of mobilisation is closely linked to the spread of panic and intimidation of the population," the source said, adding that bombings were part of the general strategy.

INTENSIFYING STRIKES

Russian forces have also stepped up strikes on military training grounds in recent weeks, prompting Kyiv's top general to order a strengthening of security measures at bases.

A missile attack on southeastern Ukraine this week killed a brigade commander. Ukrainian forces have also staged longer-range attacks on Russian bases in occupied territory as well as deep inside Russia.

Thursday's strike on Poltava came after the U.S. said it had paused some weapons shipments to Ukraine, which drew warnings in Kyiv that the move would harm Ukraine's defence against intensifying Russian air strikes and battlefield gains.

Separately on Thursday, two people were killed in a ballistic missile strike on port infrastructure in the southern Ukrainian city of Odesa, said regional governor Oleh Kiper.

Dozens of people have been killed in recent drone and missile salvoes at Ukrainian cities, including the capital Kyiv.

(Reporting by Anastasiia Malenko and Max Hunder; Additional reporting and writing by Dan Peleschuk; Editing by Timothy Heritage and Bernadette Baum)