The campaign manager for presumptive Republican presidential candidate Donald Trump is to leave his job.

A campaign spokeswoman said they were grateful to Corey Lewandowski "for his hard work and dedication".

The exact reason for Mr Lewandowski's departure is not yet clear.

In March, Lewandoski was arrested for the battery of reporter Michelle Fields after he was accused of knocking her to the ground, but a prosecutor decided not to press charges.