AT&T and Hasbro have become the latest firms to pull ads from YouTube on claims files are leaving off comments on videos of children on the platform.
The telecoms firm and toymaker follow food giant Nestle, which on Wednesday said it also had "paused" its ads.
YouTube said it had disabled comments on millions of videos that "could be subject to predatory comments". 1
The latest allegations surfaced on Wednesday, when a YouTube claimed that paedophiles were latched onto innocuous videos of children and objectifying them in the comments section
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Matt Watson also claimed time stamps had been left on videos marking child nudity.
The vlogger said ads for companies such as Nestle and Disney had run before the videos, effectively allowing YouTube to "monetize" the exploitation.
A spokesman for AT&T, America's biggest telecoms company, said: "Until Google [19459025Youcanprotectourbrandfromoffensivecontentofanykind
Hasbro said it was "pausing all advertising on YouTube, and has reached out to Google / YouTube to understand what actions they are taking to address this issue and preventing such content from appearing on their platform in the future"
According to reports, Disney and McDonald's have also suspended their ads.
And Epic Games, the maker of the popular online video game Fortnite, said it had "paused all pre-roll advertising" on the platform.
YouTube said it had taken "immediate action" at deleting offending accounts and reporting the illegal activity to authorities
It also said it had disabled comments on millions of videos that "could be subject to predatory comments".
" catch abuse more quickly, "it said.
YouTube has run into this kind of problem in the past.
Part of its system for reporting sexualised comments left on children's videos did not function correctly for more than a year, in BBC Trending investigation found in 2017.
And a host of firms including AT&T, Marks & Spencer and Audi have ads in the past after they appeared next to videos promoting conspiracy theories, white nationalism and terrorist groups.
Despite growing pressure on Google and YouTube to crack down on offensive content, the firms' advertising revenues continue to grow.
Their parent company, Alphabet, earned almost $ 137bn (£ 105bn) in revenue in 2018, up 23% from the prior year.