LONDON (Reuters) - London Mayor Sadiq Khan said on Sunday that it would be wrong for Britain to host U.S. President Donald Trump on a state visit, describing some of the U.S. leader's views on Islam as "ignorant".

Khan and Trump have a history. During the U.S. presidential election campaign, Khan was among many people who spoke out against Trump's proposed ban on Muslims entering the United States, an idea he said would play into the hands of extremists.

Trump has criticized Khan, accusing the mayor of making a “pathetic excuse” over his statement urging Londoners not to be alarmed by the presence of additional police on the streets in response to an attack in June.

RELATED: Terrorist blast on London underground train

27 PHOTOS Terrorist blast on London underground train See Gallery Terrorist blast on London underground train An injured woman reacts outside Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs LONDON, ENGLAND - SEPTEMBER 15: A police officer escorts an injured woman from the scene at Parsons Green Underground Station on September 15, 2017 in London, England. Several people have been injured after an explosion on a tube train in south-west London. The Police are treating the incident as terrorism. (Photo by Chris J Ratcliffe/Getty Images) LONDON, ENGLAND - SEPTEMBER 15: A police officer escorts an injured woman from the scene at Parsons Green Underground Station on September 15, 2017 in London, England. Several people have been injured after an explosion on a tube train in south-west London. The Police are treating the incident and terrorism. (Photo by Chris J Ratcliffe/Getty Images) Armed police officers walk through a carriage of a London underground tube train at Parsons Green station in London, Britain September 15, 2017. REUTERS/Hannah McKay A woman reacts outside Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs A man sits and waits in a London underground tube train at Parsons Green station in London, Britain September 15, 2017. REUTERS/Hannah McKay A woman reacts outside Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs Police officers walk on the road near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs An injured woman is led away after an incident at Parsons Green underground station in London, Britain, September 15, 2017. REUTERS/Luke MacGregor People react near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Hannah McKay Police officers and sniffer dogs walk near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Hannah McKay Police officers stand on the road near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs Police officers escort members of the public out of their inner cordon as they work near Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. Police and ambulance services said they were responding to an 'incident' at Parsons Green underground station in west London on Friday, following media reports of an explosion. A Metro.co.uk reporter at the scene was quoted by the paper as saying that a white container exploded on the train and passengers had suffered facial burns. / AFP PHOTO / Daniel LEAL-OLIVAS (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images) A woman walks with her dog past police cordon near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Hannah McKay Armed policemen stand outside Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs Police officers escort members of the public out of their inner cordon as they work near Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. Police and ambulance services said they were responding to an 'incident' at Parsons Green underground station in west London on Friday, following media reports of an explosion. A Metro.co.uk reporter at the scene was quoted by the paper as saying that a white container exploded on the train and passengers had suffered facial burns. / AFP PHOTO / Daniel LEAL-OLIVAS (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images) Members of the London Fire Brigade stand by cordon near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Hannah McKay People stand by an ambulance near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Hannah McKay Police vehicles line the street near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs Members of a bomb disposal squad stand in the street near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Hannah McKay People speak with a police officer outside Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs Armed policemen stand by cordon near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Hannah McKay LONDON, ENGLAND - SEPTEMBER 15: The emergency services are seen near the police cordon at Parsons Green Underground Station on September 15, 2017 in London, England. Emergency services are investigating reports of an explosion at the West London tube station. (Photo by Chris J Ratcliffe/Getty Images) An injured woman is led away after an incident at Parsons Green underground station in London, Britain, September 15, 2017. REUTERS/Luke MacGregor Staff from a local Italian restaurant hands out pizza and water from a stall near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Hannah McKay Deputy Chief Constable Adrian Hanstock of the British Transport Police makes a statement to the media after an incident at Parsons Green underground station in London, Britain, September 15, 2017. REUTERS/Luke MacGregor LONDON, ENGLAND - SEPTEMBER 15: A forensic tent is seen next to the stopped tube train at Parsons Green Underground Station on September 15, 2017 in London, England. Several people have been injured after an explosion on a tube train in south-west London. The Police are treating the incident as terrorism. (Photo by Chris J Ratcliffe/Getty Images) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

At the annual conference of his opposition Labour Party, Khan told an audience with GuardianLive that he thought having a state visit, which Prime Minister Theresa May has said is still planned, was "wrong".

"I sometimes think people are ignorant," he said, adding that it was his job to educate them.

(Reporting by William James and Elizabeth Piper; Editing by Kevin Liffey)