DUBAI, United Arab Emirates (AP) — Iran said Thursday it executed a prisoner convicted for a crime allegedly committed during the country's ongoing nationwide protests, the first such death penalty carried out by Tehran.

The execution comes as other detainees also face the possibility of the death penalty for their involvement in the protests, which began in mid-September, first as an outcry against Iran's morality police. The protests have expanded into one of the most serious challenges to Iran's theocracy since the 1979 Islamic Revolution.

Activists warn that others could also be put to dea...