Russia and Ukraine have called for foreigners to join their side in the war.
Ukraine says 20,000 volunteers from 52 countries have signed up to join an international legion.
On the Russian side, President Vladimir Putin has approved allowing foreign fighters, with the defence ministry saying 16,000 volunteers from the Middle East are ready to join.
So, what consequences will foreign fighters face under international law?
Presenter: Mohammed Jamjoom
Pavel Felgenhauer – Defence and Military Analyst.
Anthony Dworkin – Senior Policy Fellow, European Council on Foreign Relations.
Omar Ashour – Founding Chair, Doha Institute’s Critical Security Studies programme.