Flights bringing Afghan refugees to the United States have been suspended after four cases of measles were detected among recent arrivals, the White House said Friday.

The decision was made at the request of health authorities and as a precautionary measure, press secretary Jen Psaki told a briefing.

The four people with measles have been placed in quarantine and contact tracing has begun.

"All arriving Afghans are currently required to be vaccinated for measles, as a condition of entry into the United States," Psaki said.

She said vaccines against major diseases such as measles, mumps and rubella are being administered in military bases that receive Afghan refugees in the US, and that the administration is considering vaccinating those who are still at bases overseas as they wait to travel to America.

The US-led emergency airlift that preceded the US departure from Afghanistan saw more than 120,000 people evacuated from that country after the Taliban took power.

Most were Afghans considered to be in vulnerable circumstances, in particular those who feared Taliban reprisal because they had worked with US forces.