London Mayor Sadiq Khan shared death threats he received on Twitter to add a personal note to a speech at South by Southwest criticizing big tech companies and regulators for failing to stem the spread of hate, misinformation and radical viewpoints online.

Khan had keynote billing Monday at SXSW, the tech and culture conference running in Austin. The mayor said that governments have been in “dereliction of duty” when it comes to passing regulations to combat the ways technology has negatively affected society. He specifically pointed to the way technology has been used to tamper with elections, spread false information and further polarize public discourse.

“One of the biggest problems over the last few years is that politicians and governments have just been passive — sitting on their hands — while the tech revolution has happened around them,” Khan said in his remarks, which were live-streamed on Facebook.

Ultimately, he said, it's up to governments — including at the city level — to work with technology businesses and leaders to make sure that technological advancement has the proper checks. He drew parallels to the way governments dealt with the first Industrial Revolution, which prompted new laws such as labor reforms to deal with the way technology and a move toward factory work upended the world's agrarian society.

“Rather than blaming companies for innovating ahead of regulation, politicians must fix things when the regulation is out of date,” he said.

While Khan aimed his most pointed criticisms at his fellow lawmakers, he still called on companies such as Facebook and Twitter to deal more quickly with bad content on their networks.

Khan is known for being pro-business and pro-tech. He has lobbied heavily to make London a world technology hub. Like President Trump — with whom he has had a number of Twitter spats — Khan is active on social media. (In his speech, Khan said he hoped his speech would not generate new tweets from Washington.)

But as a progressive politician and London's first Muslim mayor, Khan has been a target of right-wing criticism, in person and online. In a key part of his address, Khan shared for the first time a half-dozen personal attacks he has fielded on social media.

" 'I'd pay for someone to execute Sadiq Khan,' " he read, quoting a message representative of the “loads” of comments he said he sees every day. Other harassers also called for him to be killed, referred to Khan as a terrorist or called to have all Muslims deported to “make London white again.” He said that he shared this personal abuse to ask what effect this sort of rhetoric has on people, particularly young men and women.

Khan said that tech companies must take greater responsibility for the type of content shared on their platforms. “[With] the skills and resources these companies have at their disposal — I believe it’s possible to go further and faster,” he said.

Social media firms are already under new regulatory pressure in Europe, thanks to German laws enacted in January that will fine companies that don't take down problematic content within 24 hours of it being reported.

Khan did not call for this type of regulation Monday but warned that even stricter regulation could be on its way if companies don't respond to government concerns.

“If this doesn’t happen, then more countries will start to follow or go further than what Germany has done,” he said. “Ultimately — there must be greater responsibility taken by some tech companies for the impact they’re having on the world. And, crucially, no business or industry should ever consider itself above the local rules, or laws set by democratic processes.”