A lawyer for Donald Trump has disputed polls that show the US presidential candidate is losing ground against rival Hillary Clinton.

Speaking to CNN, special counsel at the Trump Organisation, Michael Cohen, simply asked the interviewer "Says who?" when questioned about the polls.

Mrs Clinton has a 6-percentage-point lead over Mr Trump, according to the latest Reuters/Ipsos poll.

Her support has ranged from 41% to 44% since late July, with Trump's support experiencing wider shifts of between 33% and 39%.

According to the most recent poll, Mrs Clinton is favoured by about 41% of likely voters, Trump is at 35%, while 24% picked neither candidate.

A poll earlier this month showed Mrs Clinton had a 91% advantage with African-Americans over her rival.

Mr Cohen was asked about a shake-up in the Trump campaign, which is the second in less than two months.

The head of conservative news website Breitbart News, Steve Bannon, has been appointed campaign chief executive officer.

While senior adviser Kellyanne Conway has been promoted to the post of campaign manager.

Host Brianna Keilar asked Mr Cohen: "So you say it's not a shake up, but you guys are down."

"Says who?" Mr Cohen interjected - Ms Keilar replied: "Polls. Most of them. All of them?"

"Says who?" Mr Cohen repeated. Ms Keilar replied: "Polls. I just told you - I answered your question."

Mr Cohen then replied: "Which polls?", to which Keilar added: "All of them."