OTTAWA (Reuters) -TikTok has agreed to improve its measures to keep children off its website and app after a Canadian investigation found its efforts to block children and protect personal information were inadequate, Canadian privacy officials said on Tuesday.

The joint investigation into TikTok by Canada's privacy commissioner Philippe Dufresne and privacy protection authorities in the provinces of Quebec, British Columbia, and Alberta found that hundreds of thousands of Canadian children accessed TikTok each year despite the company stating its platform is not intended for people under the age of 13. 

The investigation also found that TikTok had collected sensitive personal information from "a large number" of Canadian children and used it for online marketing and content targeting.

"TikTok collects vast amounts of personal information about its users, including children. This data is being used to target the content and ads that users see, which can have harmful impacts, particularly on youth," Dufresne said at a press conference announcing the investigation's results. 

In response to the investigation, TikTok agreed to enhance age-assurance methods to keep underage users off the platform and to improve its communications so that users, particularly younger ones, understand how their data could be used, Dufresne said.

The company also agreed to changes throughout the course of the investigation, according to the privacy commissioners. They include preventing advertisers from targeting users under 18, except based on general categories such as language and approximate location, and expanding the privacy information available to Canadian users.

A TikTok spokesperson said the company is pleased the commissioners agreed to a number of its proposals "to further strengthen" its platform for Canadians.

"While we disagree with some of the findings, we remain committed to maintaining strong transparency and privacy practices," the spokesperson said in a statement. 

The spokesperson did not specify which findings TikTok disagreed with.

Canada joins governments and regulators around the world that have been scrutinizing TikTok because of concerns China could use the app to harvest users' data or advance its interests. TikTok is owned by Chinese company ByteDance Ltd, although U.S. President Donald Trump is working with China on a deal requiring TikTok's American assets to be transferred to U.S. owners.

The European Union's two biggest policy-making institutions have banned TikTok from staff phones, while the U.S. Senate in December passed a bill to bar federal employees from using the app on government-owned devices.

Ottawa began investigating TikTok's plan to invest and expand its business in Canada in 2023. The review led to a government order that required the firm to end its Canadian operations because of national security concerns, which TikTok is challenging.