Tony Wang issued an apology on his own Twitter account Friday and said anonymous threats sent out in the form of tweets would not be tolerated.
"The abuse they've received is simply not acceptable," Wang wrote. "It's not acceptable in the real world, and it's not acceptable on Twitter."
Wang stepped up after three prominent female journalists in Britain revealed they had received threats of sexual assault and bombings via Twitter. Similar threats were reported by five other women, including one member of Parliament.
The Daily Telegraph said the incidents sparked an online petition drive demanding Twitter add a "report abuse" function that would make it easier to alert the company to threats.
Wang said the abuse-reporting button was being added, and Twitter had added additional staff to its abuse-prevention department. Twitter will also work more closely with the UK Safer Internet Center.
In addition, Wang said, the Twitter rules were being updated to make it clearer that abusive tweeting will not be allowed.