A teenage girl plunged to death after losing her grip on the blanket she had tied to her apartment window in an attempt to swing into her friend's home one floor below.

The 17-year-old had been sneaking out of her 11-storey apartment in Putrajaya to meet a girlfriend who lives just one floor down, the Star newspaper reported today.

But she lost her grip and fell all the way to the ground.

Putrajaya police chief Abdul Razak Abdul Majid said the case was classified as sudden death and no foul play was suspected.

"Initial investigations showed that it was not suicide," he said.

The girl's parents had earlier forbidden her from meeting her friend but she decided to sneak out instead, through the window of her flat at 4am, in the administrative capital.

Residents awoke after hearing a loud thump and found her groaning in pain on the ground. She was rushed to the Putrajaya Hospital, where she died about an hour later, the newspaper said.