There was a heavy police and emergency services presence, including firearms officers as a precaution, following an assault which saw two teenage boys being taken to hospital.
There are unconfirmed reports this evening that this may have been a stabbing incident - but North Yorkshire Police said they will not provide any further information at this stage, other than the fact that it was an assault.
The former chair of the Friends of Valley Gardens, Jane Blayney, told the 'Advertiser that something must be done to keep the Valley Gardens a safe place for children and adults. She was volunteering in the gardens at the time of the incident, photographing trees, when she became aware that something had happened.
There has been a spate of vandalism and anti-social behaviour in the Valley Gardens in recent months, and Jane said this latest incident reiterates the need for immediate action.
She said: "I think it is dreadful that this has happened, I feel sadness and disappointment. There have been increasing problems in the Valley Gardens, and it's very concerning. We really need to think carefully about what can be done to keep it a safe place for everybody to enjoy."
Readers have also taken to social media to voice their shock at the incident. One said: "Hate not feeling safe - love Valley Gardens, having a walk or Parkrun, what is wrong with people ?
"It is very scary, you just never know what’s round that corner."
Another said: "I can't believe this has happened in our town."
Police were called at 3.30pm, and a cordon has been in place. Officers have been conducting patrols to reassure residents.
Anyone who witnessed the incident or has any information is asked to contact police on 101.
More on this news story as we get it.