Executives from Twitter and Facebook have been grilled by members of US Congress on everything from foreign propaganda campaigns to allegations of political bias on their platforms.

Just five months after Facebook CEO Mark Zuckerberg faced questioning by Congress, the company’s COO, Sheryl Sandberg, trekked to Capitol Hill for hearings of her own, alongside Twitter CEO Jack Dorsey.

Like Mr Zuckerberg’s hearing before them, Wednesday’s hearings provided little closure, but did reveal the depths of the frustration many politicians feel towards the tech titans.

During the Senate sessions, several legislators said they planned to introduce legislation to rein in companies like Facebook and Twitter. Or, as Senator Mark Warner put it: “The era of the Wild West in social media is coming to an end.”

The executives, meanwhile, openly admitted to making mistakes in the 2016 election, when the Department of Justice says Russian actors staged a widespread foreign influence campaign that went largely undetected by both Twitter and Facebook. Ms Sandberg said Facebook had been "too slow to spot this and too slow to act," while Mr Dorsey said his work on the issue was "not done – nor will it ever be".

Gadget and tech news: In pictures Show all 25 1 /25 Gadget and tech news: In pictures Gadget and tech news: In pictures Gun-toting humanoid robot sent into space Russia has launched a humanoid robot into space on a rocket bound for the International Space Station (ISS). The robot Fedor will spend 10 days aboard the ISS practising skills such as using tools to fix issues onboard. Russia's deputy prime minister Dmitry Rogozin has previously shared videos of Fedor handling and shooting guns at a firing range with deadly accuracy. Dmitry Rogozin/Twitter Gadget and tech news: In pictures Google turns 21 Google celebrates its 21st birthday on September 27. The The search engine was founded in September 1998 by two PhD students, Larry Page and Sergey Brin, in their dormitories at California’s Stanford University. Page and Brin chose the name google as it recalled the mathematic term 'googol', meaning 10 raised to the power of 100 Google Gadget and tech news: In pictures Hexa drone lifts off Chief engineer of LIFT aircraft Balazs Kerulo demonstrates the company's "Hexa" personal drone craft in Lago Vista, Texas on June 3 2019 Reuters Gadget and tech news: In pictures Project Scarlett to succeed Xbox One Microsoft announced Project Scarlett, the successor to the Xbox One, at E3 2019. The company said that the new console will be 4 times as powerful as the Xbox One and is slated for a release date of Christmas 2020 Getty Gadget and tech news: In pictures First new iPod in four years Apple has announced the new iPod Touch, the first new iPod in four years. The device will have the option of adding more storage, up to 256GB Apple Gadget and tech news: In pictures Folding phone may flop Samsung will cancel orders of its Galaxy Fold phone at the end of May if the phone is not then ready for sale. The $2000 folding phone has been found to break easily with review copies being recalled after backlash PA Gadget and tech news: In pictures Charging mat non-starter Apple has cancelled its AirPower wireless charging mat, which was slated as a way to charge numerous apple products at once AFP/Getty Gadget and tech news: In pictures "Super league" India shoots down satellite India has claimed status as part of a "super league" of nations after shooting down a live satellite in a test of new missile technology EPA Gadget and tech news: In pictures 5G incoming 5G wireless internet is expected to launch in 2019, with the potential to reach speeds of 50mb/s Getty Gadget and tech news: In pictures Uber halts driverless testing after death Uber has halted testing of driverless vehicles after a woman was killed by one of their cars in Tempe, Arizona. March 19 2018 Getty Gadget and tech news: In pictures A humanoid robot gestures during a demo at a stall in the Indian Machine Tools Expo, IMTEX/Tooltech 2017 held in Bangalore Getty Gadget and tech news: In pictures A humanoid robot gestures during a demo at a stall in the Indian Machine Tools Expo, IMTEX/Tooltech 2017 held in Bangalore Getty Gadget and tech news: In pictures Engineers test a four-metre-tall humanoid manned robot dubbed Method-2 in a lab of the Hankook Mirae Technology in Gunpo, south of Seoul, South Korea Jung Yeon-Je/AFP/Getty Gadget and tech news: In pictures Engineers test a four-metre-tall humanoid manned robot dubbed Method-2 in a lab of the Hankook Mirae Technology in Gunpo, south of Seoul, South Korea Jung Yeon-Je/AFP/Getty Gadget and tech news: In pictures The giant human-like robot bears a striking resemblance to the military robots starring in the movie 'Avatar' and is claimed as a world first by its creators from a South Korean robotic company Jung Yeon-Je/AFP/Getty Gadget and tech news: In pictures Engineers test a four-metre-tall humanoid manned robot dubbed Method-2 in a lab of the Hankook Mirae Technology in Gunpo, south of Seoul, South Korea Jung Yeon-Je/AFP/Getty Gadget and tech news: In pictures Waseda University's saxophonist robot WAS-5, developed by professor Atsuo Takanishi Rex Gadget and tech news: In pictures Waseda University's saxophonist robot WAS-5, developed by professor Atsuo Takanishi and Kaptain Rock playing one string light saber guitar perform jam session Rex Gadget and tech news: In pictures A test line of a new energy suspension railway resembling the giant panda is seen in Chengdu, Sichuan Province, China Reuters Gadget and tech news: In pictures A test line of a new energy suspension railway, resembling a giant panda, is seen in Chengdu, Sichuan Province, China Reuters Gadget and tech news: In pictures A concept car by Trumpchi from GAC Group is shown at the International Automobile Exhibition in Guangzhou, China Rex Gadget and tech news: In pictures A Mirai fuel cell vehicle by Toyota is displayed at the International Automobile Exhibition in Guangzhou, China Reuters Gadget and tech news: In pictures A visitor tries a Nissan VR experience at the International Automobile Exhibition in Guangzhou, China Reuters Gadget and tech news: In pictures A man looks at an exhibit entitled 'Mimus' a giant industrial robot which has been reprogrammed to interact with humans during a photocall at the new Design Museum in South Kensington, London Getty Gadget and tech news: In pictures A new Israeli Da-Vinci unmanned aerial vehicle manufactured by Elbit Systems is displayed during the 4th International conference on Home Land Security and Cyber in the Israeli coastal city of Tel Aviv Getty

The only company that received more criticism than Facebook and Twitter on Wednesday was Google parent company Alphabet, which refused to send CEO Larry Page to the hearing. Senators like Kamala Harris couldn't resist taking pointed jabs at the "invisible witness" in the room.

In fact, the senators heaped praise on both Ms Sandberg and Mr Dorsey for simply showing up to the hearing. The also praised the executives for the work they'd done on combatting foreign influence so far, and made it clear that further reforms on the issue should be a collaboration between the companies and the government.

Even Mr Warner said both Facebook and Twitter had "come a long way" in recognising and reigning in bad actors.

Trump: 'Google and Facebook and Twitter treat conservatives and Republicans very unfairly'

The House hearing was slightly more contentious, with Republican representatives grilling Mr Dorsey over alleged anti-conservative bias on the site. The concerns stemmed from reports that Twitter was "shadow banning" prominent Republicans by limiting their visibility in search results – reports the company has denied.

Mr Dorsey, sporting a full beard and a nose ring, shot down claims that Twitter's algorithms were specifically written to suppress conservative voices. An analysis of tweets sent by all members of the House and Senate, he said, found no statistically significant difference between how often a Democrat's tweet was viewed compared to a Republican's.

He added: "When people follow you, you’ve earned that audience. And we have a responsibility to make sure they can see your tweets. We do not have a responsibility, nor you a right, to amplify your tweets to audiences that don’t follow you."

Both hearings were interrupted at times by far-right activists like Alex Jones, the host of InfoWars, and Laura Loomer, a reporter popular among the alt-right. The protesters aimed to call attention to the alleged pro-liberal bias, but were ultimately removed from the hearings.