Twitter

"While internet advertising is incredibly powerful and very effective for commercial advertisers, that power brings significant risks to politics," company CEO Jack Dorsey tweeted.

Social media rival Facebook recently ruled out a ban on political ads.

Social media firms are under particular scrutiny ahead of US elections in 2020.

Mr Dorsey explained his position in a thread of tweets.

The social media giant has faced criticism in recent weeks for allowing players to come in for severe abuse online.

Those affected have included Manchester United's Marcus Rashford and Paul Pogba and the Chelsea pair of Tammy Abraham and Kurt Zouma.

United manager Ole Gunnar Solskjaer and Chelsea boss Frank Lampard have been quick to call for firm action to prevent the targeting of players.

Twitter said on Wednesday it has "taken action on more than 700 examples of abuse and hateful conduct related to UK football" in the past fortnight.

Twitter said it removed 936 accounts it said were being used to “sow political discord in Hong Kong”.

The network said the accounts originated in mainland China and were part of a coordinated attempt to undermine the “legitimacy and political positions of the protest movement”.

Facebook said it had, after being tipped off by Twitter, removed "seven Pages, three Groups and five Facebook accounts.”

The midfielder rarely uses Twitter to respond to media stories about him, but Williams was clearly fired up, saying those who say he's under pressure need to 'get their priorities right.'

Williams wrote that playing sport for a living can't be compared to those who are struggling to deal with far bigger problems.

"And for those that say I'm under pressure playing a game that I enjoy," Williams wrote. 

"Get your priorities right. Look at what's going on in the world.

"Kia ora @jacindaardern!," she wrote.

"It's been a big year for you & [New Zealand] - congrats!"

The 'Diamonds' singer told Ardern her year could "get even better" if she pledged funds to the Global Partnership for Education.

"I hope you & @MFATgovtNZ agree that educating every child can change the world!" she added.

The organisation is working alongside Rihanna's own charity, the Clara Lionel foundation, to provide education for children in poor countries around the world.

The @nytimesworld team, which covers international events, has about 1.9 million followers and is recognised by the social network as being a "verified account".

But on Saturday it was locked after posting a report about the Canadian prime minister.

The newspaper was told it had violated Twitter's rules about hateful conduct.

The NYT said it had taken Twitter nearly 24 hours to unlock the account and allow it to start posting again.

It normally sends up to 100 tweets a day.

Typically, prominent people, including musicians, journalists and company executives, get a blue icon on their profile after proving their identity.

However, some far-right and white-supremacist accounts have now also been verified.

Twitter founder Jack Dorsey said the scheme would now be "reconsidered".

In a statement, the company said: "Verification was meant to authenticate identity and voice, but it is interpreted as an endorsement or an indicator of importance.

"We recognise that we have created this confusion and need to resolve it."

The new limit will not apply to tweets written in Japanese, Chinese and Korean which can convey more information in a single character.

The move follows a trial among a small group of users which started in September in response to criticism that it was not easy enough to tweet.

The change is part of Twitter's plan to attract new users and increase growth.

Twitter brevity

During the test, only 5% of tweets sent were longer than 140 characters and only 2% more than 190, the social media site said in a blog post.

It said that the @realdonaldtrump account was "deactivated" by an employee, later clarifying that it was their last day in the job.

The account was down for 11 minutes, and Twitter is now investigating.

Mr Trump - who is an active Twitter user with 41.7 million followers - has not commented on the issue.

On Thursday evening, visitors to Mr Trump's page for a short time could only see a message that read "Sorry, that page doesn't exist!"

It said it would be clearer about who funded ads and to what end, especially those pushing a political agenda.

The company, like several tech firms, is keen to show it can self-regulate after it was found that Russian-backed groups were exploiting its ad platform.

Several key senators, from both sides of the US political divide, have backed measures clamping down on online ads.

The Honest Ads Act would regulate ad sales on social networks, search engines, websites or apps that have more than 50 million US visitors each month for the majority of months in a year.