It comes after a footage of a man killing himself was widely broadcast on his platform and seen by young children.
Theo Bertram, head of European public policy, said that sharing the video suggests a coordinated attack, perhaps from bot accounts.
He refused to discuss the ongoing negotiations on TikTok's future.
Mr. Bertram has been criticized by lawmakers from the Department of Digital Culture, Media and Sports who are investigating how social media platforms deal with online harm.
They were also keen to learn more about the future of the company outside of China, following President Donald Trump's threat to ban the app in the US unless a deal is reached with American companies.
Owner ByteDance is currently in talks with Oracle and Walmart about its future, but reports suggest China is unlikely to approve what it considers an unfair deal.
Mr. Bertram said he was unable to comment on the details of the ongoing negotiations.
"I think there are wider concerns about China and China's role in the world. And I think these concerns are projected on TikTok and I don't think they are always projected fairly," he told MPs.
Huge peak
When asked about how the platform handled Chinese government-sensitive content, such as protests in Hong Kong and the treatment of Uighur Muslims, he told lawmakers: "TikTok is a company outside of China and is run by a European management that has the same concerns and the same vision of the world that you have and we care about our users ".
Some of these users were recently traumatized by a clip circulating on the platform showing a US man committing suicide, and Bertram acknowledged that the company had to "do better".
Mr. Bertram explained that the company saw a huge spike in sharing the clip a week after it aired on Facebook Live.
"Following an internal review, we found evidence of a coordinated effort by bad actors to spread this video across the Internet and platforms, including TikTok.
"And we saw people searching for content in a very specific way. Often clicking on a people's profile as if they were anticipating that those people had uploaded a video."
He said the company had written to CEOs of Facebook, Instagram, Google, YouTube, Twitter, Twitch, Snapchat, Pinterest, and Reddit.
"What we are proposing is that, in the same way that these companies already work together on sexual images of children and content related to terrorism, we should now establish a partnership to deal with this type of content."
And for TikTok itself, it promised "changes to machine learning and emergency systems," as well as how algorithms that detect such content can work better with the company's content moderators.
He was also asked about reports that TikTok had removed disability or LGBTQ content.
He explained that "unfortunately" a policy was in place to not promote content that could encourage bullying, which restricted content for people with disabilities and LGBTQ content.
"This is no longer our policy," he said.
It was less clear that the company restricted the promotion of LGBTQ hashtags in Russia, saying, "Not as far as I know ... The only time we will remove that content is when we have a legal obligation to do so."