A day after an Indian student was killed in shelling in Ukraine's Kharkiv, New Delhi on Wednesday urged all its nationals to leave the city immediately even as Russia vowed to ensure the safety of Indians in the 'war-torn' country.

The Indian Embassy in Ukraine tweeted to say that all its nationals must leave Kharkiv "for their safety and security" and "reach Pesochin, Babaye or Bezlyudovka latest by 6 pm local time, on foot if need be".

Read:One Indian student dead in shelling in Ukraine, says govt

Earlier in the day, Moscow's envoy in Delhi said that they would investigate the death of Naveen Shekarappa Gyanagoudar, the 21-year-old Indian medical student who was killed in Russian shelling when he had stepped out to buy food in Kharkiv.

"We want to express our sympathy to the family of Naveen Shekarappa Gyanagoudar and to the entire Indian nation over the tragedy," Russian Ambassador-designate Denis Alipov told the local media on Delhi.

"Russia will do everything it possibly can to ensure the safety of Indian citizens in the areas of intense conflict... and a proper investigation of this unfortunate incident," he added.

On Monday night, Prime Minister Narendra Modi ordered four of his senior Ministers to rush to Ukraine's neighbouring countries to help evacuate not only Indians but also foreign nationals stranded in that country.

In a statement, the Foreign Ministry had said, "The Prime Minister pointed out that the visit of four senior ministers as his Special Envoys to various nations will energise the evacuation efforts. It is reflective of the priority the government attaches to this matter."

"Guided by India's motto of the world being one family, the prime minister also stated that India will help people from neighbouring countries and developing countries who are stranded in Ukraine and may seek assistance."

Last week, Prime Minister Modi urged Russian President Vladimir Putin to immediately halt military action against Ukraine, underscoring the need for a diplomatic solution to the standoff. 

This was after Ukraine's envoy in Delhi sought Modi's intervention in ending the Russian offensive.

Read: Leave Kyiv immediately, India tells its nationals

"Modi ji is one of the most powerful, respected world leaders. You have a privileged, strategic relation with Russia. If Modiji speaks to Putin we are hopeful he'll respond," Ukraine's Ambassador Igor Polikha told the local media on Thursday.

An estimated 15,000 Indians are said to be currently in Ukraine.