Next year's presidential election in Afghanistan has been postponed by three months, election authority sources say, BBC reported.

It was initially due in April. A new date in mid-July or early August is to be announced on Thursday.

Many potential candidates had been unable to meet registration requirements and extreme weather meant their teams could not organise for a spring date, the sources told the BBC.

It comes days after reports that the US was to withdraw thousands of troops.

The decision to postpone the presidential vote also comes after a series of problems affected parliamentary elections in October, which was disrupted by the Taliban and Islamic State group.