(CNN) -- Wladimir Klitschko has used a social networking site to challenge fellow world boxing champion David Haye to a heavyweight showdown.
The Ukrainian posted a video message on his Facebook page taunting Britain's WBA title holder, and then released it to the media on Monday.
Haye is widely expected to take on IBF and WBO champion Wladimir or his brother Vitali, the WBC belt holder, following his successful defense against American John Ruiz earlier this month.
Vitali revealed last month that the Germany-based siblings will toss a coin to see who fights Haye, and Wladimir has upped the stakes by claiming that the London-born boxer has been running scared of them.
Last year, Haye pulled out of a fight with Wladimir due to injury and then pulled out of talks with Vitali before claiming the WBA crown from giant Russian Nikolai Valuev.
"I want to send this message to boxing fans and directly to David Haye," the 34-year-old Wladimir said.
"David, you've bitched out on fighting both Klitschko brothers twice already and now is the time to make it happen. On behalf of the boxing fans around the world, I am officially calling you out to fight me.
"You can't run away from me forever, and you need to follow through with this fight to get respect. I'm ready -- what are you waiting for?"
Wladimir returned from a hand injury last month to knock out American challenger Eddie Chambers in their delayed bout, while the 38-year-old Vitali next faces Poland's Albert Sosnowski on May 29.