Image copyright AP Image caption Brian Johnson (left) is known for his trademark flat cap, and is seen here performing with founding member Angus Young

Australian rock band AC/DC are postponing the rest of their US tour after singer Brian Johnson was warned he is going deaf.

The band posted a statement on their website saying doctors had advised Johnson to stop touring immediately or "risk total hearing loss".

They said they would likely perform with a guest vocalist in rescheduled shows later this year.

Johnson, 68, from Gateshead, has been lead singer with AC/DC since 1980.

The news is the latest in a series of setbacks for the band.

How loud is too loud?

Loudness of a sound is measured in decibels (dB). Exposure to noise at or above 85 dB can damage hearing. Loud music at clubs, gigs and festivals, and through personal music players, can cause damage to your hearing. The risk of damage is determined by how loud the music is, how long you are exposed to it.

Average decibel levels:

•60 dB - ordinary spoken conversation

•70 dB - city street

•100 dB - pneumatic drill

•100 dB - maximum volume on some MP3 players

•110 dB - night club

•115 dB - rock concert

•120 dB - aeroplane taking off

Source: Action on Hearing Loss

Former drummer Phil Rudd was convicted last year of drug possession and making threats to kill. He served eight months of home detention.

In 2014, it emerged that founding member and guitarist Malcolm Young would not be joining the band on tours as he was suffering from dementia.

The band released its latest album Rock or Bust in November that year and has been touring ever since to promote it.