President Volodymyr Zelenskyy fired the chiefs of Ukraine's military recruitment centers over concerns about corruption.

"We fire all regional military commissars ... Cynicism and bribery during the war is treason," Zelenskyy said after a special meeting of the National Security and Defense Council.

"Someone took cash, someone took cryptocurrency," he said, adding that 112 criminal cases were initiated against employees of military recruitment offices, 33 persons have been charged with corruption.

He asked Valeriy Zaluzhniy, commander in chief of the armed forces, for new appointments of disabled veterans injured in the war with Russia.

The move followed a series of scandals including forced recruitment, and officers said to be taking huge sums of money for allowing exemption from conscription.

Corruption is a big concern in Ukraine, and Zelenskyy earlier this year made changes to the government and security services as part of a crackdown.

The dismissal of Odesa's head of military recruitment caused a stir last February after the former official was charged with taking bribes and raking in millions since the start of the war, which he then used to buy properties in Spain.

He had reportedly been charging people several thousand euros for certificates saying they were not eligible to fight in the war.

Ukraine has been defending itself against Russia's war of aggression for over 17 months and needs new soldiers. Kyiv ordered a general mobilization in the wake of the invasion.

Men of military age between 18 and 60 are not allowed to leave the country, with only a handful of exceptions.

Parliament is discussing extending the ban to 16- and 17-year-olds. So far, however, only reservists over the age of 28 have been called up.