Apple has urged users not to put iPhones under pillows and blankets and in other closed spaces while they are being charged overnight.

The tech giant says leaving devices plugged in for hours while sleeping can be hazardous.

This is because the charging cable, when connected to a power source, could potentially cause an iPhone to overheat and start a fire.

While this is unlikely, Apple says the risks are exacerbated when devices are stored under pillows, duvets and blankets.

“Keep your iPhone, the power adapter, and any wireless charger in a well-ventilated area when in use or charging,” Apple said in a new service announcement.

It also advised against sleeping on top of iPhones.

The new guidance is perhaps common sense, but it’s a welcome reminder for those who prefer to charge devices for seven or eight hours each night to be careful and employ best practices.

Apple also warned that third-party chargers may not always meet the required safety standards.

For this reason, it recommends using official wired and wireless charging products or at least opting for those that feature a “Made for iPhone” sticker.

The sticker is a sign that the product does meet international safety standards.

Apple says any products and adapters that fail to comply with safety standards could lead to injury.

This is true for any cables that become damaged or no longer work.

Finally, Apple also advised users to keep cables clear of any liquids, including glasses of water or coffee, as this could also increase the risk of damage or injury.