Elon Musk said his $44 billion deal to buy Twitter is “temporarily on hold.”

In a tweet posted Friday, the Tesla and SpaceX founder cited spam or fake accounts on the social media platform, pointing to a Reuters report from earlier this month on Twitter estimating less than 5% of its accounts are fake. “Twitter deal temporarily on hold pending details supporting calculation that spam/fake accounts do indeed represent less than 5% of users,” wrote Musk.

Shares of Twitter plunged 14% in premarket trading Friday. In a subsequent tweet, the billionaire said he remained “committed to acquisition.” Musk’s tweet comes a day after the social media company fired two of its top managers. Twitter said the company is pausing most hiring, except for critical roles, and is “pulling back on non-labor costs to ensure we are being responsible and efficient.”