Ukraine on Wednesday lowered the military conscription age from 27 to 25 in an effort to replenish its depleted ranks after more than two years of war following Russia’s full-scale invasion.

The new mobilization law came into force a day after Ukraine President Volodymyr Zelenskyy signed it. Ukraine’s parliament, the Verkhovna Rada, passed it last year.

It was not immediately clear why Zelenskyy took so long to sign the measure into law. He didn’t make any public comment about it, and officials did not say how many new soldiers the country expected to gain or for which units.

Conscription has been a sensitive matter in Ukraine for many months amid a growing shortage of infantry on top of a severe ammunition shortfall that has handed Russia the battlefield initiative. Russia’s own problems with manpower and planning have so far prevented it from taking full advantage of its edge.