Oxfordshire hospitals have postponed routine operations because of a high number of coronavirus patients.
Oxford University Hospitals (OUH) NHS Foundation Trust said it was experiencing "huge challenges as Covid rates in communities continue to rise".
It said patient numbers had doubled since the first wave in spring 2020.
OUH said a "significant increase" in the number of Covid patients in recent weeks had put pressure on bed spaces, operating theatres and staffing levels.
It said: "In order to meet this challenge, we are focusing on urgent and emergency care.
"We are postponing all routine inpatient and day case elective surgery on all of our hospital sites."
The NHS trust, which runs four hospitals in Oxford and Banbury, said some outpatient appointments would also be postponed.
However it said urgent surgery, including cancer operations, would continue.
Chief operating officer Sara Randalls said: "We appreciate how frustrating this will be for patients affected and we would like to apologise to them.
"These measures are necessary so that our staff can prioritise the care of the sickest patients and maintain safe patient care during this unprecedented time."