Donald Trump may be singling out London mayor Sadiq Khan because he is a Muslim, according to Diane Abbott.

The shadow home secretary branded Mr Trump's tweets about Mr Khan as "distasteful", adding she had never previously heard a US president reference a London mayor during her 30 years in Parliament.

She added it was hard to escape the conclusion that this may be as Mr Khan is "of the Muslim faith", a claim Home Office minister Victoria Atkins declined to respond to.

Mr Trump dubbed Mr Khan a "disaster" and a "national disgrace who is destroying the city of London" following violent crimes over the weekend in the capital.

Ms Abbott's remarks came during an urgent Commons question on violent crime after four people died in suspected murders in four days in London.

She said: "In relation to the president of the United States implying that the mayor of London is responsible for the rise in violent crime, the mayor must be held to account like any other politician.

"But in 30 years in Parliament I've never heard a president of the US reference a London mayor at all. It's hard to escape the conclusion that President Trump may be singling out Sadiq Khan because he is of the Muslim faith.

"Does the minister accept that if that were true, many people would find it distasteful?"

Ms Atkins replied: "I'm going to decline to respond about President Trump for the simple fact that I'm sure... we all have at the forefront of our minds today the four families who have been affected in the most terrible way this weekend.

"I hope she will forgive me if I don't dive into the political pool on today of all days."

For the SNP, Stuart McDonald said the "totally wrong response was to tweet or retweet racist jibes" about Mr Khan, before he highlighted Scotland's public health approach to violence.

Ms Atkins earlier described the weekend's events as a "stark reminder that serious violence is a continuing threat", adding: "This included a fatal stabbing in (Labour MP Jim Fitzpatrick's) Poplar and Limehouse constituency, fatal stabbings in Tooting and West Ham, and a fatal shooting in Plumstead.

"These incidents are subject to police investigations, arrests have been made in some cases, but I know that the House will understand that I cannot go into any more detail at this point on these particular cases.

"These events are a stark reminder that serious violence is a continuing threat. There is no single or simple answer and the police, local authorities, police and crime commissioners and others are working with us, taking action on a number of fronts."

Labour's Lyn Brown (West Ham) said: "Last night my community was violated yet again by another murder. It's been a terrible few years in West Ham with nine young lives lost."

She added "proper funding" is needed, noting: "We need police officers. We don't need overtime payments, we actually need something fundamental that is going to raise the level of activity."

Ms Atkins later told MPs that legislation to allow knife crime prevention orders to be piloted could be introduced "in the autumn".

Labour former policing minister Vernon Coaker said the country will be watching the exchanges with a "sense of incredulity" as he questioned where Home Secretary Sajid Javid was.

He said: "Where's the passion, the indignation, the horror about what is happening on our streets, not just in London but across the country?"

Mr Coaker said the Government was offering "peanuts" to deal with rising violent crime, adding: "It's a national emergency, Cobra should be called and the Government should bring to it the same enthusiasm, the same urgency, the same dynamism if there was a terrorist attack on our country, God forbid.

"It's about time the minister got a grip on this... where's the Home Secretary? He's absent without leave, he's busy fighting the Tory leadership campaign, he should be here doing his day job."

Ms Atkins said there was a "little bit too much anger in politics at the moment", adding this would not solve the problem of serious violence.

The minister later clashed with Labour's Marsha De Cordova (Battersea), accusing her of "doing sort of funny actions in her chair" as she listed details of the Government's response.

By Elizabeth Arnold and Richard Wheeler