A surge of stabbings in London was blamed Monday for the city overtaking New York's monthly murder tally for the first time in modern history.

Fifteen people were murdered in London during February, compared to 14 in New York, according to police figures.

The British capital also suffered 22 fatal stabbings and shootings in March, higher than the 21 in New York.

There have been 10 fatal stabbings in London in the last 19 days, following on from the 80 fatal stabbings recorded in the city last year.

London's murder rate has grown by nearly 40 percent in three years, while police figures show that New York's has fallen by 87 percent since 1990, raising pressure on mayor Sadiq Khan and Metropolitan Police chief Cressida Dick.

Despite the recent surge, New York, which has a slightly smaller population than London, has still suffered more murders since the start of the year.

The right-wing Daily Express tabloid on Monday ran with a headline urging "Sadiq act now!"

Sean Yates, Scotland Yard's head of knife crime, said part of the rise could be blamed on courts not enforcing the "two strikes" law aimed at jailing those caught with a knife twice.

Police chief Dick meanwhile blamed social media for the soaring rate, with 31 fatal stabbings so far this year.

"There's definitely something about the impact of social media in terms of people being able to go from slightly angry with each other to 'fight' very quickly," she told the Times on Saturday.