Former boxing champion Evander Holyfield has failed to wrestle away the World Boxing Association heavyweight title from John Ruiz, after the two Americans battled to a 12-round draw.

Holyfield was denied a fifth heavyweight title in Saturday's bout in Mashantucket, Connecticut.

Fans jeered the boxers, who spent much of the fight clutching, shoving and mauling rather than trading punches.

After the decision, the 39-year-old Holyfield said he still intends to become boxing's undisputed heavyweight champion.

In an earlier fight, American Tim Austin retained his International Boxing Federation bantamweight title with a unanimous 12-round decision over Ratanachai Vorapin of Thailand.

Meanwhile in Berlin, undefeated World Boxing Organization light heavyweight champion Dariusz Michalczewski of Germany kept his title in a punch-filled bout, stopping Jamaica's Richard Hall in the 11th round. Michalczewski now has 38 knockouts in his 45 victories.