Petra Kvitova says she has sustained a "severe" injury to her left hand, but feels lucky to be alive after being attacked in her apartment by an individual with a knife.

News of a reported attack on two-time Wimbledon champion Kvitova by an intruder emerged on Tuesday.

The Czech, currently ranked 11th in the world, soon provided details of the incident through a message posted via her official Twitter and Facebook accounts.

It read: "Thank you for all your heartwarming messages. As you may have already heard, today [Tuesday] I was attacked in my apartment by an individual with a knife.

"In my attempt to defend myself, I was badly injured on my left hand. I am shaken, but fortunate to be alive.

"The injury is severe and I will need to see specialists, but if you know anything about me I am strong and I will fight this.

"Thank you all again for your love and support and now I would appreciate some privacy while I focus on my recovery."

It had earlier been announced that the 26-year-old would not compete in the Hopman Cup next month due to a foot injury. 

The Czech suffered a stress fracture in her right foot and a slower-than expected recovery led her to withdraw from the team event that starts on January 1.