KYIV: Ukraine's defence ministry urged military-age citizens to update their data at army enlistment offices and "overcome their fear" in a campaign launched on Thursday as a summer counter-offensive grinds through its third month.

The campaign, which draws on slickly-produced videos and photo testimonials of prominent soldiers describing their fears, aims to break down a major obstacle in army recruitment, Deputy Defence Minister Hanna Maliar said.

"We're all living people and we all overcome this fear in order to win," she said, noting that military-age citizens are duty-bound to keep their personal data at draft offices up-to-date.

The campaign comes with Ukraine likely facing tougher challenges in recruiting as the war with Russia, now in an brutally attritional phase, nears the 18-month mark.

As she outlined the campaign, Maliar was careful to say that not all those who updated their personal data would automatically be mobilised into the army and that not all those who are mobilised would end up in a combat zone.

President Volodymyr Zelenskiy announced a general mobilization after Russia's February 2022 full-scale invasion and military reservists between the ages of 18 and 60 are eligible for conscription.

"Bravery conquers fear," ran one of the campaign's slogans. "Everyone has fears in a war. I do too," a Ukrainian soldier who fought in Bakhmut was quoted as saying.

Maliar also pledged to stamp out corruption from the recruiting process.

"Trust between citizens and (recruiting centres) is important," Maliar added in comments carried by an official military platform. "Right now we're taking a step toward establishing this trust."

The military has been hit by scandals involving graft or heavy-handed recruitment tactics.

Zelenskiy signed a decree on Thursday, formalising a decision taken last week to fire all the heads of regional recruitment offices after a nationwide investigation turned up scores of cases involving corruption and abuse.

"This system should be run by people who know exactly what war is and why cynicism and bribery during war is treason," he said.

The moves come as Ukraine is trying to make headway in a counteroffensive to retake occupied territory that has been hampered by minefields and Russian defences in the southeast.