San Francisco, Nov 15 (IANS): As several advertisers pause spending on Twitter, GroupM, part of WPP which is the world's biggest ad company, is reportedly telling its clients that buying ads on the platform is now a "high-risk" venture.

According to Platformer, GroupM with $60 billion in annual media spend is concerned about Elon Musk's takeover of Twitter.

"Given the recent senior departures in key operational areas (specifically Security, Trust & Safety, Compliance), GroupM have updated Twitter's brand safety guidance to high risk," the company reportedly told clients in an internal Slack message.

"While they understand that our policies remain in place, they feel that Twitter's ability to scale and manage infractions at speed is uncertain at this time," GroupM wrote.

GroupM works with companies like Google, L'Oreal, Bayer, Nestle, Unilever, Coke and Mars.

The ad company joins IPG and Omnicom in warning clients about running their ads on Musk's platform.

Omnicom, in an internal memo, suggested its clients to "pause activity on Twitter in the short term", under a note titled "Twitter - Continued Brand Safety Concerns".

The memo listed recent events that could have "potential serious implications" for businesses that run advertisements on the platform.

Additionally, the memo highlighted a number of important challenges for advertisers, including the mass layoffs of Twitter's trust and safety teams, high-profile executives' resignations, and the growth of "verified" impersonator accounts.