Ukrainian President Volodymyr Zelensky approved the National Mobilization Order on the night of the 24th (local time), AP, AFP and dpa news agency reported.
The national mobilization order refers to measures to convert military power and national infrastructure to a wartime system and to mobilize human resources and materials in relation to a national or international emergency.
According to this measure, which will take effect for 90 days, all conscripts and reserve forces in Ukraine are called.
Next, President Zelensky confirmed the number of citizens and reservists obligated to serve in the military, and instructed the government to invest the necessary resources for mobilization measures.
On the evening of the 24th, Ukrainian Customs Commissioner Daniil Menshikov said on Facebook that men aged 18 to 60 are banned from leaving the country.
In a video speech released on the morning of the 25th, President Zelensky said at least 137 military and civilian deaths were recorded on the first day of the Russian invasion, and more than hundreds were injured.
"Russia is killing people and turning peaceful cities into military targets. It's dirty and unforgivable," he said.
The day before, he released a video of his speech, saying he would "distribute weapons to everyone who wants to defend the sovereignty of the country."
"What we hear today is not just the roar of fighter jets and the roar of missiles, but the sound of a new 'iron curtain' coming down," he added.
Zelensky also feared that Russian forces could invade Ukraine and other European countries in the future.