'Shaq' to retire

One of the most accomplished players in the game, the 39-year-old O'Neal made the announcement by posting a video on the social media website Twitter.

"We did it. Nineteen years baby. I want to thank you very much, that's why I'm telling you first, I'm about to retire. Thank you, talk to you soon," he said in the message.

The physically imposing O'Neal, who stood 7 feet one inches (2.16 metres) and weighed 325 pounds (147 kilogram), was a force under the basket, 10 times leading the NBA in field goal percentage thanks to his overpowering low-post game and thunderous dunks.

He averaged 23.7 points and 10.9 rebounds a game over his long career, was named to 15 All-Star teams and was a member of the United States team that won the gold medal at the 1996 Atlanta Olympics.

He scored 28,596 points in the NBA, the fifth highest total ever, and was 12th overall in rebounds and seventh in blocked shots.

"What a career for Shaq Diesel!!" LeBron James tweeted.

"The most dominating force to ever play the game. Great person to be around as well. Comedy all the time!!" The much-heralded O'Neal was taken as the first overall pick in the 1992 NBA Draft by the Orlando Magic following a stellar college career at Louisiana State University.

After joining the Los Angeles Lakers as a free agent in 1996, O'Neal became part of a championship run with the young Kobe Bryant that produced three successive NBA titles from the 1999-2000 season.

O'Neal was named NBA Finals MVP in each of those triumphs and earned the league's Most Valuable Player award in 2000.

A feud between O'Neal and Bryant over the focus of the offense led the Lakers to trade the big center to the Miami Heat in 2004, and two years later Shaq teamed up with Dwyane Wade to win another NBA title.

He was later dealt to the Phoenix Suns and Cleveland Cavaliers, where he played with James, before spending an injury-marred campaign this season with the Boston Celtics, averaging 9.2 points and 4.8 rebounds in 20.3 minutes a game.

A gentle giant off the court with a wry sense of humour, the massive man known around the world as "Shaq" had one glaring weakness, a difficulty in sinking free throws.

His dismal 52.7 percent accuracy from the charity stripe led opposing teams to adopt a "Hack-a-Shaq" tactic, where late in close games they would immediately foul O'Neal to send him to the free-throw line.

He was also quite accomplished off the court.

Over the years, O'Neal has released four rap albums, appeared in films and starred in his own reality shows, Shaq's Big Challenge and Shaq Vs.