Americans have been expressing their shock and outrage over Thursday's fatal shooting of five police officers by snipers in Dallas. Many of the voices came from the business community, including several high-profile entrepreneurs such as Dallas Mavericks owner  Mark Cuban, who offered reactions on social media.

The attack occurred less than a month after Cuban made a $1 million donation to his home city's police department following the mass shooting at a nightclub in Orlando. Cuban tweeted shortly after the events in Dallas, lamenting the deaths of the officers.


Cuban also added this tweet in support of the city.


Twitter co-founder Jack Dorsey tweeted a live Periscope feed of the police department's press conference, which attracted more than 200,000 viewers. 


Dorsey later retweeted Georgia congressman and civil rights activist John Lewis's reaction to the shootings, calling for unity and gun control legislation.


Apple CEO Tim Cook also took to his Twitter account to react to the events, including a link from Lewis showing when he was arrested 55 years ago for using a "white" restroom:


Facebook founder Mark Zuckerberg posted on his company's platform on Thursday before the Dallas shootings took place, referring to the Facebook live video that captured the aftermath of the police shooting of a black motorist in Minnesota.