The tech giant admitted production and sales were affected by disruption in China, and said "worldwide iPhone supply would be temporarily constrained", but stopped short of revealing the likely cost.
In a statement, the company said: "We do not expect to meet the revenue guidance we provided for the March quarter."
Apple explained it was "experiencing a slower return to normal conditions" than anticipated, and revealed sales of Apple products would be lower during this time.
The firm added: "While our iPhone manufacturing partner sites are located outside the Hubei province -- and while all of these facilities have reopened -- they are ramping up more slowly than we had anticipated.
"The health and well-being of every person who helps make these products possible is our paramount priority, and we are working in close consultation with our suppliers and public health experts as this ramp continues.
"These iPhone supply shortages will temporarily affect revenues worldwide.
"The second is that demand for our products within China has been affected. All of our stores in China and many of our partner stores have been closed.
"Additionally, stores that are open have been operating at reduced hours and with very low customer traffic."