Olympic heptathlon champion Jessica Ennis-Hill has pulled out of the world athletics championships in Moscow because of an injury.

Ennis-Hill has been struggling with an Achilles injury but returned to compete in the Anniversary Games at London's Olympic Stadium over the weekend. However, she finished a disappointing fourth in the 100-meter hurdles and eighth in the long jump.

Doping bans

Nine Turkish track and field athletes have been banned for two years each after testing positive for anabolic steroids.

The IAAF says six of the athletes are women, including two teenagers.

The IAAF says six cases involve field athletes testing positive for stanozolol at Turkey's national university championships held in May at Bursa. Stanozolol is the steroid used by Canadian sprinter Ben Johnson at the 1988 Seoul Olympics.

On Wednesday, Ennis-Hill says she is "not where I want to be both regarding pain and also form" and adds "to say I am gutted is an understatement."

Ennis-Hill made decision with coach Toni Minichiello, who says there were fears that "competing at the world championships would cause further damage, making any rehab more difficult."

The 27-year-old Ennis-Hill was looking to regain the world title she lost to Tatyana Chernova of Russia in 2011. Chernova has also withdrawn with an injury.