Twitter is banning all political advertising from its platform worldwide, saying "political reach messages should be earned not bought", but Facebook has defended its stance that politicians have the right to free speech.
Jack Dorsey, Twitter's CEO, announced the decision on the social media platform and said banning political adverts was not about "free expression."
"This is about paying for reach. And paying to increase the reach of political speech has significant ramifications that today’s democratic infrastructure may not be prepared to handle. It’s worth stepping back in order to address," he wrote.
But Facebook's Chief Executive Mark Zuckerberg defended his company's position and said private companies should not censor politicians.
"We need to be careful about adopting more rules that can restrict what people can say," he said.
"I don't think it's right for politicians to be censored."
Facebook has faced criticism since it disclosed earlier in October that it will not fact-check ads by politicians or their campaigns.
Mr Zuckerberg told US Congress last week that politicians have the right to free speech on Facebook.
The issue suddenly arose in September when Twitter, along with Facebook and Google, refused to remove a misleading video ad from US president Donald Trump’s campaign that targeted former vice president Joe Biden, a leading Democratic presidential candidate.
In response, Democratic Senator Elizabeth Warren, another presidential hopeful, ran an ad on Facebook taking aim at its Mr Zuckerberg.
The ad falsely claimed that Mr Zuckerberg endorsed Mr Trump for re-election, acknowledging the deliberate falsehood as necessary to make a point.
Critics have called on Facebook to ban all political ads.
This includes CNN chief Jeff Zucker, who recently called the policy of allowing lies ludicrous and advised the social media giant to sit out the 2020 election until it can figure out something better.
Twitter chief executive Jack Dorsey tweeted the worldwide change on Wednesday, saying the company is recognising that advertising on social media offers an unfair level of targeting compared to other mediums.