India on Friday expressed its gratitude to Ukraine, Russia and the Red Cross for helping it evacuate its citizens from various Ukrainian cities in the midst of the ongoing war.

External Affairs Minister S Jaishankar, in a post on Twitter, specifically mentioned that the evacuation of Indian students from the northeastern city of Sumy was "particularly challenging".

He also thanked the neighboring countries of Ukraine -- Romania, Hungary Poland, Slovakia, and Moldova -- for their "exceptional support" in bringing back the Indian nationals under the evacuation mission 'Operation Ganga'.

"Operation Ganga, undertaken at the direction of Prime Minister Narendra Modi has delivered due to both leadership and commitment. We are thankful to all those who facilitated its objectives," Jaishankar said.

"Our particular gratitude to the authorities in Ukraine and Russia as well as the Red Cross for the evacuation assistance. Ukraine's neighbours -- Romania, Hungary, Poland, Slovakia and Moldova gave us exceptional support. My sincerest thanks to them," he said.

India evacuated around 600 Indian nationals from conflict-ridden Sumy city on Tuesday after Russia and Ukraine provided a humanitarian corridor for their exit following New Delhi's intense diplomatic engagement with the two sides.

India has brought back around 18,000 Indians under 'Operation Ganga' which was launched on February 26, two days after Russia launched its military offensive on Ukraine.

"We are grateful to NGOs, individual volunteers, corporates, our airlines and the Indian Air Force who worked so tirelessly in this exercise," Jaishankar said.

The external affairs minister also appreciated the role played by his ministerial colleagues Jyotiraditya Scindia, Kiren Rijiju, Hardeep Singh Puri and General (Retd) VK Singh in the evacuation mission.

Puri, Rijiju, Scindia and Singh were in Hungary, Slovakia, Romania and Poland respectively to coordinate evacuation efforts.

"Appreciate the contribution of my four ministerial colleagues, Shri Jyotiraditya M Scindia, Shri Kiren Rijiju, Shri Hardeep Singh Puri, and General (Retd) VK Singh whose presence on the ground made a big difference," Jaishankar said.

"Applaud our Embassy in Ukraine and Team MEA for their dedicated efforts in a difficult conflict situation," he added.