Washington (dpa) - The head of the Senate Commerce Committee demanded Thursday that Twitter staff brief the Congressional body by July 23 on the nature of this week's hack of prominent accounts, as lawmakers start to enforce oversight and an FBI probe got under way.

Influential figures such as former president Barack Obama, Microsoft co-founder Bill Gates, Tesla founder Elon Musk, Democratic presidential contender Joe Biden, rapper Kanye West, Amazon chief Jeff Bezos and others saw their accounts briefly hacked on Wednesday, posting a message for a Bitcoin scam.

"It cannot be overstated how troubling this incident is, both in its effects and in the apparent failure of Twitter's internal controls to prevent it," said Senator Roger Wicker in a letter to Twitter chief Jack Dorsey.

Wicker noted that the hack appeared to be for financial gain, but the same methods could be used for more nefarious purposes.

"It is not difficult to imagine future attacks being used to spread disinformation or otherwise sow discord through high-profile accounts, particularly through those of world leaders," Wicker said.

Notably, President Donald Trump is prone to announce policy over social media.

The FBI confirmed it is investigating the incident, saying in a statement emailed to dpa that "the accounts appear to have been compromised in order to perpetuate cryptocurrency fraud."

New York Governor Andrew Cuomo said he was directing a "full investigation" by the state into the hack, as he raised concerns over cybersecurity in the run-up to November's presidential election.

"The Twitter hack and widespread takeover of verified Twitter accounts is deeply troubling and raises concerns about the cybersecurity of our communications systems, which are critical as we approach the upcoming presidential election," Cuomo said in a press release.

Twitter said in an update late Thursday that it believed "approximately 130 accounts were targeted by the attackers in some way as part of the incident."

"For a small subset of these accounts, the attackers were able to gain control of the accounts and then send Tweets from those accounts," the company tweeted.

Twitter has said it believes there was a "coordinated social engineering attack."

To get control over its platform again, Twitter suspended certain functions for hours. Those have largely been restored.

The company said that it will continue to work with impacted account owners over the next several days and that it was "taking aggressive steps to secure our systems while our investigations are ongoing."