One of the two Chinese peacekeepers killed in South Sudan last year was a former cucumber farmer from Sichuan province, the other a husband and father from Shandong.

When they were killed on patrol near a refugee camp in Juba, capital of the world’s newest country, there was a small eruption on Chinese social media, where some commentators vented frustration at their country’s increasing involvement in distant lands. “Fight those who have injured us, don’t just condemn,” wrote one.

China has 750 peacekeepers in South Sudan and more than 2,000 in Africa as a whole, including in the Democratic Republic of Congo and Liberia — a bigger deployment than any other permanent member of the UN Security Council. That Beijing has been willing to put lives at risk so far afield shows how its economic ambitions have morphed into political involvement, straining a decades-old strategy of non-interference in foreign affairs.