Facebook Inc's CEO Mark Zuckerberg on Wednesday defended his company's role in U.S. elections and rejected assertions in a tweet from U.S. President Donald Trump that the social network was against him.

Zuckerberg has been on the defensive for weeks over revelations that Russian agents bought ads on Facebook and created fake accounts to inflame political tensions in the United States ahead of the 2016 presidential vote.

In a Facebook post on Wednesday Zuckerberg said both Trump and liberals were upset about ideas and content on Facebook during the campaign.

"Trump says Facebook is against him. Liberals say we helped Trump," Zuckerberg said in his post.

"Both sides are upset about ideas and content they don't like. That's what running a platform for all ideas looks like."

Zuckerburg noted that the 2016 campaign was the first in the United States where the internet was a primary way candidates communicated and said the ability of candidates and voters to interact was a good thing.

He also pointed to "get out the vote" efforts that had spurred almost 2 million people to register to vote.

In the same post, Zuckerberg said he regretted saying after the election that it was "crazy" to think that misinformation on Facebook changed the outcome of the election, adding that the comment was "dismissive."

He held firm that Facebook's biggest role in the election was as a platform for candidates and citizens to communicated directly with one another regarding issues.

Earlier on Wednesday, Trump's tweet criticized Facebook as "anti-Trump" and suggested the company could have colluded with other media outlets that opposed him.

"Facebook was always anti-Trump.The Networks were always anti-Trump hence,Fake News, @nytimes(apologized) & @WaPo were anti-Trump. Collusion?" the tweet read.

Early morning Twitter tizzies have become a hallmark of Trumptarget="_blank"'>