Elon Musk put his $44-billion deal for Twitter Inc. "temporarily on hold" on Friday while he awaits data on the proportion of its fake accounts, sending the shares in the social media platform plunging.

Twitter shares fell 17.7% to $37.10 in premarket trading, their lowest level since Musk disclosed his stake in the company in early April and subsequently made a "best and final" offer to take it private for $54.20 per share.

Meanwhile, Tesla shares, against which Musk has secured $6.25 billion in funding for the acquisition, were up about 5%.