Ukraine said on Wednesday it had detained a Chinese father and son, both suspected of spying on its prized Neptune anti-ship missile programme, a key part of Kyiv's growing domestic arms industry critical to its defence against Russian invaders.

Ukrainian President Volodymyr Zelensky has accused China of deeper involvement in Russia's invasion than it is letting on. Beijing has repeatedly said China is not a party to or participant in the Ukraine war, and does not provide weapons to either side.