Mayor of London Sadiq Khan Friday declared a 'major incident' in London due to increasing COVID-19 infection rates in the capital, which is threatening to overwhelm the health system.

City Hall said rise in the number coronavirus cases are "putting immense pressure on an already stretched NHS", as the number of coronavirus patients on breathing support is up by 42 percent in one week.

Currently there are 7,034 coronavirus patients in London hospitals, which is 35 percent more than during the first peak of the pandemic. The London Ambulance Service is taking up to 8,000 emergency calls every day, which is 2,500 more calls than a usual busy day in the capital.

Khan said "If we do not take immediate action now, our NHS could be overwhelmed and more people will die," asking Londoners to "stay at home unless it is absolutely necessary."

A major incident is defined as being 'beyond the scope of business-as-usual operations.' It usually involves "serious harm, damage, disruption or risk to human life or welfare, essential services, the environment or national security."