Prosecutors in Florida have said they have filed criminal charges against a 17-year-old accused of masterminding the massive hack of high-profile Twitter users in mid-July.

Investigators identified the Florida resident as the "mastermind" of the cyber attack and arrested him in Tampa, Hillsborough state attorney Andrew Warren said.

The attack which Twitter said resulted from a "phone spear phishing" attack enabled the hackers to take control of accounts of famous people such as Bill Gates, Elon Musk and former US president Barack Obama and trick people into sending more than $100,000 worth of Bitcoin.

"This defendant lives here in Tampa, he committed the crime here, and he'll be prosecuted here," Mr Warren added.

Meanwhile, the US Department of Justice said today that two more people have been charged in relation to the attack.

In a statement, the Department said one of the men has an address in England and the other in Orlando, Florida.

Earlier, Twitter said the hackers gained access to the system with an attack that tricked a handful of employees into giving up their credentials, according to a company update.

Twitter said in a security update that the 15 July incident by bitcoin scammers stemmed from a "spear phishing" attack which deceived employees about the origin of the messages.

The hackers "targeted a small number of employees through a phone spear phishing attack," according to a Twitter Support statement.

The company said: "This attack relied on a significant and concerted attempt to mislead certain employees and exploit human vulnerabilities to gain access to our internal systems."

Twitter said that following the incident it has "significantly limited access to our internal tools and systems" and is taking additional steps to tighten security.

The massive hack affected at least 130 accounts.

The official accounts of Apple, Uber, and Kanye West were among those affected.

Faked tweets were sent from 45 accounts, according to Twitter, and the hackers accessed private messages of 36 and downloaded Twitter data from seven.

Law enforcement is also investigating the incident which has raised concerns about the security of the platform increasingly used for conversations on politics and public affairs.