(Reuters) - Advertisers are grappling with Twitter's new ownership under Tesla (NASDAQ:) boss Elon Musk, who once tweeted "I hate advertising".

Below are reactions from some of the companies:

Allianz (ETR:) SE

German insurer and asset manager Allianz will halt paid advertising on Twitter for now, a spokesperson said on Monday, after Elon Musk completed acquisition of the social media platform.

Audi of America

The Virginia-based U.S. unit of luxury automaker Audi - a Volkswagen (ETR:) Group brand - said it had paused advertising on Twitter and would "continue to evaluate the situation."

Ford Motor (NYSE:) Co

A spokesperson for Ford told CNBC that the automaker is not currently advertising on Twitter and had not been doing so prior to Musk's deal.

Inc (NYSE:)

The company known for its Cheerios and Lucky Charms cereals has paused advertising on Twitter, a company spokesperson said on Thursday, adding it would monitor the direction Twitter takes and evaluate its marketing expenditure.

General Motors Co (NYSE:)

The largest U.S. automaker temporarily paused paid advertising on Twitter after Musk completed his takeover. The automaker said it was "engaging with Twitter to understand the direction of the platform under their new ownership."

Gilead Sciences (NASDAQ:)

The HIV drugmaker and its unit Kite are in the "process of pausing advertising" on Twitter, monitoring its ad spending and waiting to better understand how community standards and content moderation will be handled.

Havas Media Group

Havas Media Group, Vivendi (OTC:)'s advertising unit, is recommending that its clients "temporarily pause their Twitter ads in the U.S. because of concerns about the company's ability to monitor its content", the Wall Street Journal reported.

The Interpublic Group of Companies Inc (NYSE:)

The global advertising and marketing services firm recommended that its clients temporarily pause advertising on Twitter, the Wall Street Journal reported.

L'Oreal SA

The cosmetics maker said it had not suspended ad spending on Twitter, denying a Financial Times report from Nov. 2 that said it had, citing sources familiar with the matter.

Mondelez (NASDAQ:) International

The maker of Oreos has paused advertising on Twitter, the Wall Street Journal reported on Thursday, citing sources familiar with the matter.

Inc (NYSE:)

Drugmaker Pfizer Inc has reevaluated its decision to advertise on Twitter, following Elon Musk's deal to take the firm private, WSJ reported.

Stellantis N.V.

The carmaker said it would pause all paid advertising on Twitter until the Dodge, Fiat and Chrysler parent company had a clearer understanding of the future of the platform under the leadership of Elon Musk.

United Airlines

The airline said it had suspended ad spending on Twitter.

Volkswagen AG (OTC:)

The automotive conglomerate, which includes brands such as Lamborghini, Audi, Seat and Porsche among others, recommended that its brands pause paid advertising on Twitter until further notice.