Kirsty Williams said it was part of a "national effort to reduce transmission of coronavirus".

However, the Children's Commissioner for Wales has criticised the decision as disruptive to education.

A number of counties have also said primary schools will close earlier, including Cardiff and Swansea.

Ms Williams said it was important to take a "clear, national direction" to ease the pressure from schools, colleges, local councils and parents and carers.

"Every day, we are seeing more and more people admitted to hospital with coronavirus symptoms," she added.

"The virus is putting our health service under significant and sustained pressure and it is important we all make a contribution to reduce its transmission."

She said the advice from Wales' Chief Medical Officer, Dr Frank Atherton, was to implement the online learning plan "as soon as is practicable".

"Having spoken to local education leaders, I am confident that schools and colleges have online learning provision in place," added Ms Williams.

"This will also be important in ensuring that students are at home during this time, learning and staying safe.

"Critically, and this is very important, children should be at home.

"This is not an early Christmas holiday, please do everything you can to minimise your contact with others."

The latest data shows the infection rate across Wales is averaging more than 370 cases for 100,000 people, with 17% of tests now coming back positive.

It means the reproduction (R) number in Wales has now reached 1.27, with infections doubling in 11.7 days.

But Children's Commissioner Sally Holland said move was "not the right decision" for children and young people in Wales and had yet to see any scientific advice to support the move.

"Whilst accepting the severity of the public health emergency and the responsibilities all of us have to keep each other safe, this decision compounds the disruption to our children's education over the last few months," she said.

Which primary schools will close early?

The announcement does not extend to primary or special schools, with the education minister "encouraging" them to remain open.

However, a number of local authorities have announced they will also be halting face-to-face learning early.

Schools in Swansea will all move to online blended learning on Monday, so Friday is the last day in the classroom for primary school pupils.

Pembrokeshire and Ceredigion, parents have been sent emails telling them classrooms will close after Monday.

Carmarthenshire council has said primary and special schools will be given the choice to move to online learning or stay open from Tuesday.

Cardiff council said the final day in class will be Tuesday.

"The move is designed to enable students to remain at home in the run up to Christmas to try to halt the rise in infection rates," said a statement from Cardiff city officials on Thursday evening.

The neighbouring Vale of Glamorgan will close primary schools on Wednesday, 16 December.

Some local authorities had already announced plans to close schools early.

Blaenau Gwent shut classrooms on Wednesday, with infection rates in the county now standing at nearly 600 cases for 100,000 people.

In north Wales, Flintshire and Wrexham had decided to shut schools on Friday, with infection rates running at 175 and 230 cases per 100,000.

Bridgend, Caerphilly and Rhondda Cynon Taf councils had also planned to shut early next Wednesday, 16 December.

The teaching union NAHT had called for schools in Wales to shut this Friday, and be replaced with online classes.

But the union said it was "bitterly disappointed" the move did not include primary or special schools.

"This decision ignores Welsh government's own advice on pre-isolating before seeing extended family over the Christmas holidays," said Laura Doel from the union.

"Many parents will simply vote with their feet and keep children at home anyway."

The Association of School and College Leaders has supported the Welsh Government's announcement.

"This is obviously a difficult decision but the public health advice is very clear that this needs to happen to tackle Covid infection rates in Wales and reduce transmission of the virus," said its director in Wales, Eithne Hughes.

"However, we urge the Welsh Government and local authorities to keep a close eye on the situation in primary schools and take appropriate action if needed."

The decision has also been welcomed by the National Education Union Cymru and Unison.

'Blanket approach'

But the move has been criticised by the education leader at one north Wales council.

Huw Hilditch-Roberts, of Denbighshire council, said the announcement was a "blanket approach based on what is happening in the south".

The rate of infection in the county is 101.4 per 100,000.

"Any decision to close schools should be made on the data, and the data in our area doesn't support the decision," he told the Local Democracy Reporting Service.

"I feel this could result in a community spike because it will be harder to manage with more children in the community for longer."

Responding to the announcement, Plaid Cymru's education spokeswoman Siân Gwenllian said on-site provision must be made for all younger learners, and children of key workers "who can't make alternative arrangements".

She said every secondary school pupil must also have suitable devices for accessing online lessons, adding: "Accessing education through Xboxes and mobiles phones is not good enough."

The Welsh Conservatives said the decision was another instance off "confusing messages" from the Welsh Government.

"There is no doubt that the situation is grave in parts of Wales, but I would have preferred targeted interventions where needed, not another blanket ban," said their education spokeswoman in the Senedd, Suzy Davies.