Facebook has defended its live streaming service despite it being said to have sparked last week’s sniper attack on Dallas police in which five officers died.

Diamond Reynolds streamed on Facebook Live after police killed her boyfriend.

A day later a bystander used Facebook Live on his smartphone to stream the sniper attack. Within the hour, TV network CNN was re-broadcasting the footage.

In a Facebook post, CEO Mark Zuckerberg wrote that while the images “are graphic and heartbreaking,” such videos also “shine a light on the fear that millions of members of our community live with every day”.