Twitter has said it would add labels to election-related advertisements and say who is behind each of them.

The moves comes after a threat of regulation from the US over the lack of disclosure for political spending on social media. 

Twitter said it would start a website so people could see identities of buyers, targeting demographics and total ad spend by election advertisers. 

Facebook launched a similar overhaul of political ads last month.

Social media firms and the political ads that run on their websites have generally been free of the disclaimers and other regulatory demands that US authorities impose on television, radio and satellite services.

Calls for that to change have grown, however, after Twitter, Facebook and Alphabet's Google said in recent weeks that Russian operatives and affiliates bought ads and used fake names on their services to spread divisive messages in the run-up to the 2016 US presidential election. 

Russia has denied interfering in the election.

Citing Russia-linked ads, Facebook last month said it for the first time would make it possible for anyone to see any political ads that run on Facebook, no matter whom they target. 

The attempts at self-regulation by Facebook and Twitter have not satisfied lawmakers.

Twitter said its changes would take effect first in the US and then globally. 

The new approach to ads would be visible in people's Twitter feeds, where election ads would have the label "promoted by political account," the company said. 

"To make it clear when you are seeing or engaging with an electioneering ad, we will now require that electioneering advertisers identify their campaigns as such," Bruce Falck, Twitter's general manager of revenue product, said. 

Twitter said it would limit targeting options for election ads, although it did not say how, and introduce stronger penalties for election advertisers who violate policies. 

The company said it would also allow people to see all ads currently running on Twitter, election-related or otherwise. 

Twitter's latest move would not tackle its longstanding problem with fake or abusive accounts that some users and lawmakers also blame for influencing last year's US election. 

Unlike Facebook, Twitter allows anonymous accounts and automated accounts, or bots, making the service more difficult to police.