LONDON (AP) — Princess Anne sustained minor injuries and a concussion following an incident on an estate in southwest England, the Buckingham Palace said Monday.

The 73-year-old sister of King Charles III was hospitalized as a precautionary measure for observation and is expected to make a full recovery, the palace said, adding the incident happened on Sunday on the Gatcombe Park estate.

Though the exact cause of the injuries is unconfirmed, there were horses in the area. Her medical team said that her head injuries were consistent with a potential impact from a horse’s head or legs.

“The king has been kept closely informed and joins the whole royal family in sending his fondest love and well-wishes to the princess for a speedy recovery,’’ the palace said in statement.

The princess was walking within the protected perimeter of the estate when the incident occurred, Britain's Press Association said.

Emergency service were called to the estate and she was treated at the scene before being transferred to Southmead Hospital in Bristol. Her husband, Vice Admiral Tim Laurence, accompanied her.

Anne is one of the hardest working members of the royal family, having stepped in and taken more duties in light of Charles’ cancer diagnosis. Her engagements for the days ahead will be postponed and she will not attend the state dinner being held in the honor of the emperor of Japan.