TORONTO – Queen Elizabeth II attended a memorial Thursday for four slain Mounties in what was the deadliest attack on Canadian police officers in 120 years.

The queen and her husband, Prince Philip, began the third day of their visit at the Royal Canadian Mounted Police national training center in Regina in the western province of Saskatchewan, where she met privately with the families of the slain Mounties.

The queen resumed her western tour to celebrate the centennials of Saskatchewan and Alberta joining the Canadian confederation.

The 79-year-old monarch is Canada’s symbolic head of state and has visited the country 22 times since her coronation.