Donald Trump has announced staff changes that include campaign manager Corey Lewandowski leaving the GOP nominee's team. In a move that has reportedly been several months in the making, Lewandowski and Trump have parted ways.

Reports are currently unclear on whether or not the campaign manager quit his role or was asked to leave, although rumours of in-fighting abound.

"The Donald J. Trump Campaign for President, which has set a historic record in the Republican primary having received almost 14 million votes, has today announced that Corey Lewandowski will no longer be working with the campaign," campaign spokeswoman, Hope Hicks, said in a statement seen by The New York Times.

"The campaign is grateful to Corey for his hard work and dedication and we wish him the best in the future."

It is expected Lewandowski, who was rumoured to have a strained relationship with the US political press, will be succeeded by Trump's campaign chairman Paul Manafort.

Lewandowski, who faced charges that were later dropped over allegedly grabbing a Breitbart reporter's arm at a Trump campaign event, according to The Hill, is thought to have clashed with Manafort after he took up the campaign chairman role in March.

The campaign manager's departure was also celebrated by some within Trump's camp, including aide Michael Caputo, who tweeted: "Ding, dong the witch is dead!" shortly after the announcement.

There are just weeks to go until the Republican convention, in which Trump is currently expected to be announced as the official GOP presidential candidate for the November election.