India on Thursday was firming up contingency plans including activating alternate air routes to evacuate its citizens from Ukraine as the spectre of a massive Russian offensive loomed over the eastern European country after President Vladimir Putin announced a military operation.

The Ministry of External Affairs (MEA) held a series of high-level meetings to put into operation certain contingency plans in view of the rapidly changing situation in Ukraine.

Official sources said given that the Ukrainian airspace was closed for civilian aircraft, alternate evacuation routes are being activated to bring back the Indians, especially the students.

They said additional Russian speaking officials have been sent to the Indian embassy in Kyiv and are being deployed in countries neighbouring Ukraine.

The sources said the Indian embassy in Ukraine is functional and its advisories should be followed carefully.

"Contingency plans are being put into operation," said a source

The sources said India is closely monitoring the "rapidly changing" situation in Ukraine and its immediate priority is to assist the Indians.

"We are closely monitoring the rapidly changing situation. Focus is on safety and security of Indians, particularly students," said a source.

It said the control room set by the Ministry of External Affairs a few days back is being expanded and made operational on a 24x7 basis.

Ukraine closed its airspace to civilian flights in view of high risk to safety.

"The government is looking at ways to extend assistance to Indians there," said a source.

According to estimates, over 15,000 Indians are currently staying in Ukraine.

It is learnt that a series of meetings are underway to assess the situation and ways to extend assistance to Indians in that country.

The situation in Ukraine deteriorated after President Vladimir Putin announced a military operation in Ukraine, triggering serious concerns over the possibility of a full-scale military confrontation between the two countries.

Following Putin's announcement, Ukrainian President Volodymyr Zelensky said an "invasion" could be the beginning of a "big war" in Europe.