A major incident has been declared across the Thames Valley as the number of Covid-19 cases in the area continues to increase.
The area's Local Resilience Forum (LRF) said its three counties had moved "to Major Incident status".
The LRF includes councils, the NHS and emergency services covering Berkshire, Buckinghamshire and Oxfordshire.
Milton Keynes Council leader Peter Marland said "pressure on our NHS is growing".
Case rates in the Thames Valley
The area has two districts just below 1,000 cases per 100,000 people in the week to 31 December - Slough in Berkshire (993.1 cases per 100,000 people) and South Bucks (978.1 cases per 100,000 people).
South Oxfordshire had the highest increase in case rates in the area, with rates rising by 60% week-on-week.
With the exception of Milton Keynes, every district in Buckinghamshire, Berkshire and Oxfordshire had a week-on-week rise in case rates.
The move comes after Buckinghamshire Council announced a major incident in that county on 30 December.
Labour's Mr Marland said: "The pressure on our NHS is growing. It is right that tougher restrictions are in place now, and that across Thames Valley all agencies work together to spread the pressure on services."
However, he added that Milton Keynes was "not at that critical level yet, and across our partners we have been working to a major incident level of co-ordination for 10 months".
He said the major incident status should be used to make sure schools in Milton Keynes were prioritised in the roll-out of new vaccines.
"Despite the restrictions, our infection rate is one of the highest in the south east, and Milton Keynes is one of the few areas where both our primary and secondary schools are closed," he said.
"Our younger population demographic, the size of our schools and the new variant means that I would not want schools to reopen until a school vaccine programme is rolled out.
"Reopening schools without a vaccine programme will be a recipe for disaster and probably just prolong our high infection rate, the level of restrictions and increase the economic pain."
In a statement, the LRF said the decision came "in response to growing pressure being experienced across Thames Valley partners".
It said it would enable communities to work together "in response to the range of challenges being faced".