People walk past the Houses of Parliament in London, Britain, on Jan. 1, 2021. (Photo by Ray Tang/Xinhua)

Schools and colleges across Britain closed on Tuesday ahead of a national lockdown as the country battled to control surging coronavirus cases that are threatening to overwhelm its healthcare system.

The tough new measures were announced Monday even as Britain began rolling out the Oxford-AstraZeneca shots, a possible game-changer in fighting COVID-19 worldwide, and as vaccine programs in the US and Europe stumbled.

Scotland began its lockdown Tuesday, while Prime Minister Boris Johnson said all of England, the UK's largest nation, would close down from Wednesday - possibly into mid-February.

The latest virus moves are aimed at containing a severe wave of infections with a new coronavirus strain believed to spread faster.

"With most of the country already under extreme measures, it's clear that we need to do more, together, to bring this new variant under control while our vaccines are rolled out," Johnson said in a televised address.

Similar to a first March-June lockdown in 2020, the new moves include the closure of schools and a ban on leaving home for all but exercise and essential shopping.

As Britain ramped up its inoculation program Monday with the shots developed by the University of Oxford and AstraZeneca, pressure was growing on European authorities to speed up their vaccine approvals process.

The European Medicines Agency is yet to approve the Moderna vaccine, and it has said a decision on the AstraZeneca jab is unlikely in January.

German Chancellor Angela Merkel and state leaders were expected Tuesday to extend a shutdown in Europe's top economy as coronavirus deaths mounted despite tough restrictions in the run-up to the holidays.

The ease of storage and use of the Oxford-AstraZeneca vaccine compared with the Pfizer-BioNTech and Moderna alternatives could mean greater access for less wealthy nations in the fight against the coronavirus, which has infected more than 85 million people with more than 1.8 million known deaths.

Mexico on Monday followed India in approving the Oxford-AstraZeneca vaccine for emergency use.

The efforts to accelerate vaccinations come as concerns grow about the potentially more transmissible variant spreading out of control.

The Chinese firm Sinopharm said Monday its vaccine - with a claimed effectiveness of 79 percent - remains effective against the new variant.

In the US, the worst-hit ­nation in the world, the rollout of vaccines has been plagued by logistical problems and ­overstretched hospitals and clinics.