Police in India's capital city on Saturday said they had arrested a local freelance journalist on allegations he was passing "sensitive information" to Chinese intelligence officers.

North Korea's state news agency said on Saturday an Australian student who was expelled from the country after 10 days' detention had committed "spying acts" through his work with foreign media.

Poland said Friday it had arrested a Chinese telecoms executive suspected of spying for China, with local media identifying him as a Huawei director.

The United States is demanding the immediate return of a retired US Marine detained by Russia on spying charges, and wants an explanation of why he was arrested, US Secretary of State Mike Pompeo said on Wednesday.

Kevin Garratt, a Canadian held in China for two years and charged with spying, returned to Canada on Thursday in what was a diplomatic triumph for Prime Minister Justin Trudeau.