WASHINGTON: A wave of tweets in apparent hacking swept through Twitter on Wednesday, with more than half a dozen high-profile accounts - belonging to US presidential candidate Joe Biden, former US President Barack Obama, billionaire Bill Gates, and rapper Kanye West, among others - used to solicit bitcoin donations.

The cause of the breach was not immediately clear, but the scale and the scope of the problem suggested that it was not limited to a single account or service.

Twitter said it was investigating what it called a "security incident" and would be issuing a statement shortly. Shares in the social media company tumbled almost 5 percent in trading after the market close before paring their losses.

Some of the tweets were swiftly deleted but there appeared to be a struggle to regain control of the accounts. In the case of billionaire Telsa Chief Executive Elon Musk, for example, one tweet soliciting cryptocurrency was removed and, sometime later, another one appeared.

Among the others affected: Amazon founder Jeff Bezos and the corporate accounts for Uber and Apple.

Biden's campaign was "in touch" with Twitter, according to a person familiar with the matter. The person said the company had locked down the Democrat's account "immediately following the breach and removed the related tweet." Tesla and other affected companies were not immediately available for comment.

Publicly available blockchain records show that the apparent scammers have already received more than $100,000 worth of cryptocurrency.

Update:

Twitter now says the hack was caused by, "a coordinated social engineering attack by people who successfully targeted some of our employees with access to internal systems and tools."

Twitter says it has locked access to all affected accounts and will restore access only when they can "do so securely."