article: The Times reported that telecoms firms AT&T and Verizon, as well as car rental company Enterprise and pharmaceutical giant GSK, have withdrawn all non-search advertising. An investigation by the newspaper found major brands were appearing next to YouTube videos promoting extremist views - generating revenues for the creators. The company has apologised and promised better tools for advertisers. Despite Google’s efforts to contain the row, which began in the UK earlier this week, it appears to have now caught the attention of the US advertising industry - creating a huge problem for Google as it seeks to reassure brands their ad spend is not funding hate groups. According to The Times, Verizon’s advertisements were appearing along side videos made by Wagdi Ghoneim, an Egyptian cleric who had been banned from the US over extremism, and Hanif Qureshi, whose teachings inspired the assassination of a Pakistani politician. “We are deeply concerned that our ads may have appeared alongside YouTube content promoting terrorism and hate,” AT&T said in a statement on Wednesday. "Until Google can ensure this won’t happen again, we are removing our ads from Google’s non-search platforms.” The UK-based investigation led more than 250 brands to pull their advertising. In a blog post published on Monday, Google’s chief business officer Philipp Schindler announced the company was expanding its policies on hate speech to include videos targeting vulnerable groups. In response to the latest boycott from the US brands, Google said on Wednesday: “We’ve begun an extensive review of our advertising policies and have made a public commitment to put in place changes that give brands more control over where their ads appear.” “We’re also raising the bar for our ads policies to further safeguard our advertisers’ brands.” Google is the dominant player in online advertising, and ads are by far the company’s biggest source of money. In 2016, the firm generated $80bn in ad revenue - accounting for almost 90% of the firm’s total income for the year. Of the boycotts announced on Wednesday, both Verizon and AT&T have major online advertising ambitions of their own. Verizon in particular recently agreed to purchase embattled web portal firm Yahoo for $4.48bn - a deal it hopes will help it compete with Google for ad sales. Follow Dave Lee on Twitter @DaveLeeBBC. You can reach Dave securely through encrypted messaging app Signal on: +1 (628) 400-7370
summary: At least four major US firms have pulled millions of dollars in advertising from Google’s platform amid rows over extremist content.