The number of cases of the Delta variant in Wales has almost doubled within a week to 178, the country’s health agency has said.

Public Health Wales (PHW) warned community transmission of the variant may have begun and urged people to get vaccinated and keep to social distancing measures.

But the alert is tempered by the latest figures for coronavirus deaths which shows that fewer people are dying from Covid-19.

On Tuesday, PHW said the number of confirmed cases of the mutated strain of the virus had increased by 81 since June 3.

PHW said in a statement: “The organisation is alerting the public that Wales may slowly be beginning to experience localised community transmission of the variant, with increasing evidence of cases with no travel history.”

At Tuesday’s Welsh Parliament plenary, Mark Drakeford said the “troubling” rise in variant cases “gives us all pause for thought”.

Health minister Eluned Morgan said the figures showed “coronavirus has not gone away” and brought a “new level of uncertainty”.

“We hope we can contain cases and prevent this variant from spreading further,” she told the Senedd.

“But I think we have to be realistic and we do expect the number of cases in Wales continuing to increase.”

The majority of cases are located in clusters in both South Wales and North Wales, particularly in Llandudno and Penrhyn Bay where community testing has been increased.

Scientists believe the latest variant is more transmissible than the Kent or Alpha variant which has been overtaken as the UK’s dominant strain, though they have been unable to discount the contribution of increased social mixing due to eased restrictions.

Latest evidence shows that both the Pfizer and AstraZeneca vaccines are effective against the variant after two doses.

Dr Giri Shankar, incident director at PHW, said though the increase of variant cases was expected it was still “concerning” to see.

“The increase is likely to be driven in part by the transmissibility of the variant, which we know is easier to catch than the previously dominant Alpha variant,” he said.

“However, increased mixing also contributes to transmission, and this may be playing a part too.

“The spread of the Delta variant in Wales is a reminder that we should not become complacent, even as rates of coronavirus across Wales remain low.”

But while variant cases are on the rise, the number of deaths from Covid in Wales continues to go down as more people are vaccinated, with PHW reporting no new deaths from Covid for 10 days in a row before Monday.

The Office for National Statistics (ONS), which publishes figures of registered deaths in a wider range of settings where the virus is confirmed or suspected, reported just three deaths in the last week, the lowest number since September last year.

First Minister Mark Drakeford announced on Monday that all adults in Wales will be offered a vaccine by next Monday, six weeks ahead of schedule, while the Welsh Government has pledged to offer second doses to all adults by the end of September 2021.

More than 85% of people in Wales have now had their first dose of the vaccine, and nearly half have completed a two-dose course.