The deadline came on Tuesday for Ukrainian men of fighting age to register their personal information to the military under a new mobilization law.

The law was passed in May to address a shortage of soldiers in the fight against Russia's invasion of Ukraine by tightening mobilization. It requires the men aged 18 to 60 to provide their address and family information to the military within the time limit.

Monday saw around 50 people lining up for registration at a government office in the capital Kyiv.

A 25-year-old man said the registration is an important thing to do. He said skills he gained from his architectural education may help him on the frontlines.

A 28-year-old male said he thinks situations on the frontlines are severe. He said he cannot fully support the new law, but that there is no other option available.

A survey by a Ukrainian research firm released last month found that 52 percent of the respondents said they disagree with the new law.

The Ukrainian defense ministry announced that around four million people have completed the registration as of Sunday.

President Volodymyr Zelenskyy on Monday stressed that plans to mobilize troops were proceeding smoothly.