The communication line will be established for the "mothers, fathers, wives, grandparents, Russian occupiers," according to Anton Gerashchenko, adviser at the Internal Affairs Ministry.
"On this phone line, you can find out whether your relatives are still alive, taken prisoner, injured, and you can decide when and how to take the body of your deceased relative," he said.
"If your loved one is in our captivity, you can leave a short message for your husband, son," Gerashchenko added.
Russian President Vladimir Putin ordered the military intervention Thursday, days after recognizing two separatist-held enclaves in eastern Ukraine. He claimed that Moscow had no plan to occupy the neighboring country but wanted to "demilitarize" and "denazify" Ukraine.
Fighting on the third day of the intervention is said to have reached the streets of Ukraine’s capital Kyiv.
While Ukrainian President Volodymyr Zelenkskyy has pledged to defend the country, Western countries have announced sanctions on Moscow, including measures targeting President Vladimir Putin and Foreign Minister Sergey Lavrov.
According to UN High Commissioner for Refugees Filippo Grand, more than 150,000 Ukrainian refugees have now crossed into neighboring countries, including Poland, Hungary, Moldova and Romania.
"Displacement in Ukraine is also growing but the military situation makes it difficult to estimate numbers and provide aid," he said in a tweet.