A grandmother had her necklace cut from her during a burglary as her husband had a knife pointed at his throat, police said.
The couple, in their late 50s, were asleep when two masked men entered their bedroom at their home in Ilford, east London, early on Monday morning.
One attacker put his foot on her chest to restrain her and used a pair of pliers to cut her necklace off.
The second burglar stood over her husband and pointed the knife at him.
The woman was then forced to hand over other jewellery.
The assailants fled through the back garden when they were disturbed by other people in the house.
Police were called by the couple's 20-year-old granddaughter at about 03:00 GMT.
The attackers wore dark clothing, the Met said. One was white and the other black and both were in their mid-to-late 20s.
Det Con Sophie Mostyn said: "This was a terrifying ordeal for the victims and it has left them extremely distressed.
"We are determined to catch those responsible and put them before the courts."
Anyone with information has been urged to contact police.