Stockholm  - Swedish 100-metre hurdler Susanna Kallur has decided to drop plans to compete in the upcoming world championships in Berlin as she is still not completely recovered after undergoing surgery for a stress fracture.

"It feels like time is up," Kallur told Swedish broadcaster SVT Sports in an interview on Sunday evening.

"If I go to the world championships, I want to be very well prepared and I will not be able to be that. I want to focus on many good years in future," she added.

The world championships take place August 15-23.

Kallur, 28, in November underwent an operation for a stress fracture in a shin, and in June removed a metal plate.

In 2006 she won the European Championships in the 100-metre hurdle event, and was 4th at the 2007 worlds in Osaka, Japan.

Stefan Olsson, national head coach of the Swedish Athletics Association, backed Kallur's decision and said it was necessary not to push things.

Susanna Kallur's twin sister Jenny has a similar injury and is also to miss out on the world championships. (dpa)