Photographs published Sunday of Prince William's girlfriend Kate Middleton, clad in khaki on a Scottish hunting trip, have rekindled speculation that the pair will soon announce their engagement.

British Sunday newspapers ran pictures showing Middleton, 25, on a stag hunting expedition at the royal family's Balmoral estate alongside William's father, Prince Charles.

Click here to read about Kate's hunting trip in the London Times.

One shows Middleton, in jeans and a camouflage jacket, lying on her stomach as she lines up her rifle for a shot, reportedly at a practice target.

The Sunday Telegraph said it was the first time Middleton had been photographed with Charles, "fueling speculation that she is about to become engaged to Prince William."

The Sunday Times said the pictures suggested that Middleton's "induction into the royal family appears to have stepped up a notch."

Buckingham Palace refused to comment on the trip, saying it was a private activity.

William and Middleton met at St. Andrews University in Scotland and dated for several years, but announced their split in April as speculation swirled that they were about to marry.

Middleton had been pursued by photographers outside her London home and nightclubs in scenes that drew comparisons to the coverage of William's mother, Princess Diana, before her death in 1997.

Newspapers reported this summer that the pair had rekindled their romance, and last week the couple were photographed by paparazzi as they left a London nightclub.

William's spokesman complained about the "threatening" behavior of the photographers, which came the same week as pictures of Diana being driven from the Ritz Hotel in Paris in 1997 were released as part of an inquest into her death.