Washington, Jul 1 (IANS): With the highly transmissible Delta variant accounting for more than a quarter of the new coronavirus cases in the US, the country's health authorities were are reconsidering the mask mandate for the public.

The Delta variant, which is more contagious and aggressive than others, reached nearly every state and accounted for 26.1 per cent of the total confirmed cases, according to the US Centers for Disease Control and Prevention (CDC).

"I'm concerned about the Delta variant," Xinhua news agency quoted the country's Surgeon General Vivek Murthy as saying on Wednesday.

"And I am worried that what we are seeing in terms of a plateauing of cases nationally but also an increase in cases in many small sections of the US, that that is, in fact, being driven by the Delta variant."

There is still a lot of virus circulating in the US, and close to 300 people are still dying daily from the coronavirus, Murthy said in an interview with CNN, citing data from recent weeks.

Spikes in coronavirus cases are "entirely avoidable, entirely preventable" with vaccination, said Anthony Fauci, White House chief medical advisor.

Places with low vaccination rates are especially vulnerable to the Delta variant, experts have said.

The spread of the super-contagious Delta variant is prompting new lockdowns around the world and spurring new warnings from public health officials.

The World Health Organization, citing the rise of Delta, has encouraged fully vaccinated people to continue wearing masks.

In Los Angeles County, the pace of Delta's spread has prompted officials to reinstate mask guidance for public indoor spaces -- regardless of vaccination status.

Public health officials in Los Angeles County on Tuesday strongly recommended that local residents wear masks indoors in public places such as "grocery or retail stores, theatres and family entertainment centres, and workplaces when you don't know everyone's vaccination status".

The Delta variant is expected to become the dominant coronavirus strain in the US, CDC Director Rochelle Walensky said recently.

Experts and officials are concerned that coronavirus variants, especially the highly transmissible Delta variant, will continue to drive up new cases.

With half the US population still not fully vaccinated, experts warned it could cause a resurgence of Covid-19 in the fall.