A warning has been issued to people to avoid a reservoir in Gwynedd following the discovery of a blue-green algal bloom.

Natural Resources Wales (NRW) has issued the warning for Llyn Celyn, Bala.

An NRW spokesperson said: “Following investigations and sampling by our officers, a blue-green algal bloom has now been confirmed at Llyn Celyn.

“As a precaution, please avoid contact with the water where algae or scums are visible and keep dogs out of the water. “While not all blooms are toxic, some can be harmful to people and animals.

“Warning signs have been installed around the lake to advise visitors.

“If you spot a suspected blue-green algal bloom elsewhere, please report it using our online form at https://shorturl.at/RzpT5 or call our incident hotline on 03000 65 3000.”