Photo: AFP

The co-founder of WhatsApp has joined the chorus of voices against social media giant Facebook.

Brian Acton joined the #DeleteFacebook movement as he took to Twitter on Tuesday to say, ?It is time. #DeleteFacebook.?

Acton?s advice is notable because WhatsApp is owned by Facebook. The social network acquired his company for $19 billion in 2014.

The California-based social media giant is facing an onslaught of criticism at home and abroad over revelations that a firm working for Donald Trump's presidential campaign harvested and misused data on 50 million members.

Calls for investigations came on both sides of the Atlantic after Facebook responded to the explosive reports of misuse of its data by suspending the account of Cambridge Analytica, a British firm hired by Trump's 2016 campaign.

What did Cambridge Analytica do?

Here is some of what is known about the company

The backlash has spooked investors, leading shares in the company to fall by more than 9% over the last two days ? wiping almost $50 billion off the valuation of the company.

Facebook CEO Mark Zuckerberg and COO Sheryl Sandberg have remained quiet throughout the scandal, inviting yet more criticism from analysts and investors.