After the Russian invasion, unexploded shells and mines will take years to be removed, warned a Ukrainian minister.

Ukrainian Interior Minister Denys Monastyrsky said in an interview with The Associated Press that a lot of shells and mines have been fired at the country.

It will take years, not months, to defusing them.

He told The AP that Ukrainian soldiers placed land mines across the country to prevent Russian forces from moving. There are mines in airports.

Western countries will need to help remove those mines and defibrillate the shells.

We won't be able to remove the mines from all that territory, so I asked our international partners and colleagues from the European Union and the United States to prepare groups of experts to de-mine the areas of combat and facilities that came under shelling.

There is still no sign of Russia retreating as the war between the two countries continues for more than three weeks.

More than 3 million Ukrainians have fled since the beginning of the invasion, according to data from the United Nations Refugee Agency. More than one million Ukrainians fled the country in the first week.

The agency estimates that as many as 4 million people will leave their homes in the coming weeks because of the conflict in Ukraine.

Ukrainian soldiers are fighting a difficult battle as Russia continues to advance. The Ukrainian army said on Friday that its soldiers have blocked off two vital routes into the capital city.

The enemy has been stopped at a distance of almost 70 kilometers from the city's right bank, which makes it impossible to carry out fire, except for rocket fire. The advance has been stopped on the left bank. The enemy is shooting at us. Oleksandr Hruzevych, deputy chief of staff, said that the main ways of attack were blocked.