Potential human remains, including a jaw with teeth still attached, have been recovered from the largest reservoir in the US, officials said, as an ongoing drought causes water levels to drop across western states.

The US National Park Service said it received reports of apparent skeletal remains at Boulder Beach on Lake Mead, Nevada, on 16 August.

"National Park Service rangers and the Las Vegas Metropolitan Police Department responded to the scene," the service said in a statement seen by the BBC's US partner CBS.

The service added that the incident "remains under investigation, and no additional information is available at this time".

A woman and her friend spotted the bones while visiting the Nevada side of the reservoir, which is located on the border with Arizona.

Dianelis Molina Cruz told CBS affiliate KLAS: "My friend was playing with the rocks in the lake, and then he grabbed the jaw. And when he looked, he saw the teeth and everything."

Her friend Noel De Leon suggested the low water levels at Lake Mead contributed to the recovery of the potential human remains.

"The water looks very low compared to where it should be," he said. "As the water goes down, the skeletons come up."

Water levels at Lake Mead, which is the largest reservoir in the US, have been declining since 2000.

The US Bureau of Reclamation said that water levels at the reservoir dropped to 1,040ft (316m) above sea level last week – considerably below the previous record low set in July 2022.

The reservoir is in Clark County, most of which is in moderate drought, according to the US Drought Monitor.

Droughts have been worsening in recent years, something scientists say is being driven by climate change.

Persistent hot summer weather has been causing water levels to drop in rivers and lakes in several countries – leading to unexpected discoveries.

In Hungary, the bodies of two World War Two German soldiers were recovered from the Danube River in Budapest earlier this month. Alongside the remains was a largely intact German army Wehrmacht motorcycle.

Other remnants of World War Two have appeared in the Danube recently, including a broken-up hull near Prahovo in Serbia.

And in the UK, low water levels at a reservoir in Rutland have uncovered the remains of the village of Nether Hambleton, which was demolished and flooded to create the reservoir.