NEW YORK (BLOOMBERG) - YouTube said it will launch a separate website for children after the Google-owned service was criticised and investigated for showing inappropriate videos to kids on its main site.

The new site, an online version of the YouTube Kids mobile app, will go live later this week, according to a statement posted on Wednesday (Aug 28) by the company.

YouTube also said its Kids app and website will get new categories for different ages.

Preschool will be for children who are four years old and younger.

"Younger" is for ages five to seven and "Older" is for those aged eight to 12.

"We know that what is great content for a four-year-old may not be great content for a 10-year-old, which is why we want to make it easier for parents to select the right content for their kids on YouTube Kids," the company said in the blog post.

YouTube has been criticised for letting inappropriate, misleading and sometimes violent videos spread on its service. For years, executives were unable or unwilling to address the problem as they pursued aggressive viewer "engagement" targets, Bloomberg News has reported.

Videos targeting children have been particularly problematic, partly because YouTube doesn't manually review all clips and its software can't easily identify what content is appropriate for young viewers.

The Federal Trade Commission is looking into whether YouTube breached the Children's Online Privacy Protection Act (COPPA). The agency has reached a settlement with YouTube, but has not released the terms. To satisfy regulators, YouTube officials are planning to end "targeted" ads on videos that kids are likely to watch.

On Wednesday, YouTube warned parents that it still won't be able to spot all inappropriate videos.

"Our systems work hard to exclude content not suitable for each of these age categories, but not all videos have been manually reviewed," the company said.

"If you find something inappropriate that we missed, you can block it or flag it for fast review."