An Indian student was killed by shelling in the eastern Ukrainian city of Kharkiv on Tuesday, India’s foreign ministry said, and Delhi stepped up demands for safe passage to evacuate thousands of its nationals trapped in the war zone.

Russian forces are laying siege to Kharkiv and other major cities, and firing artillery at them, a Ukrainian official said.

Indian foreign ministry spokesman Arindam Bagchi said the Ambassadors of Russia and Ukraine had been called in “to reiterate our demand for urgent safe passage for Indian nationals who are still in Kharkiv and cities in other conflict zones.”

In a post on Twitter, he added that the ministry was in touch with the family of the student, who he did not name.

India, which is an ally of Russia and has its own militarized territorial disputes, has not condemned Moscow’s invasion of Ukraine, to the displeasure of the United States and other Western partners.

Indians make up around a quarter of the 76,000 foreign students in Ukraine, by far the largest number, according to Ukrainian government data.

New Delhi has evacuated around 4,000 Indians in the last month, but some 16,000 remain trapped since Russia invaded the former Soviet republic last week, according to the latest data from India’s foreign ministry.

The Indian government has sent four ministers to neighbouring countries to assist in the rescue efforts.

The situation in Kharkiv is of particular concern, a foreign ministry source told Reuters. An Indian team has been positioned in Belgorod, a Russian city about 70 kilometres (45 miles) away close to the Ukrainian border, but has been unable to evacuate citizens because of the fighting, the source said.