An advocacy group has offered Donald Trump sensitivity training to help him better understand people with disabilities after he appeared to mock a reporter.

At issue is what The New York Times interprets as Mr Trump's attempt to "ridicule the appearance" of journalist Serge Kovaleski.

Mr Trump challenged recollections by Mr Kovaleski and others about the September 11 aftermath during a speech.

The Republican presidential candidate has made unsubstantiated claims that thousands of Muslims in New Jersey were seen celebrating the attack.

Mr Trump said: "Poor guy, you oughta see this guy."

He then gestured in a fashion that appeared to imitate Mr Kovaleski's movements.

The Ruderman Family Foundation says Mr Kovaleski has a congenital condition affecting joint movement.