Bob Arum is least blamed by respondents in a poll regarding who should be blamed for the fight controversy.

LOS ANGELES (AP) — Representatives for Manny Pacquiao and Floyd Mayweather Jr. wrapped up a lengthy mediation session on Tuesday with no word on any progress on the drug-testing issues endangering the boxers' prospective March 13 bout.

Pacquiao promoter Bob Arum and Mayweather's promotional team all said they had been told to make no public comments after their meeting in Santa Monica. The mediation finished nearly nine hours after it began in front of Daniel Weinstein, a retired federal judge.

Arum's Top Rank and Mayweather's representatives at Golden Boy Promotions agreed to the mediation in an effort to resolve their dispute over the methods and frequency of drug testing for the bout, which will be held at the MGM Grand Garden in Las Vegas if a compromise is reached.

Although both fighters have agreed to extensive urine testing, Mayweather has demanded random blood testing as well. Pacquiao has balked at unlimited blood testing, instead proposing two blood tests before the fight and another immediately afterward.

Pacquiao also complicated the negotiations by filing a lawsuit last week alleging Mayweather and most of his camp's key players defamed him by falsely accusing him of using performance-enhancing drugs.

Neither side would say whether more mediation will be held on Wednesday, but the length of Tuesday's meeting appeared to be a positive development for the potential fight. If little progress could be made, the session likely would have been scrapped early, with the sport's top two fighters moving on to replacement bouts instead of meeting in what's expected to be the richest fight in boxing history.

After impressive pay-per-view numbers in their most recent bouts last year, both fighters stand to make more than $25 million in their welterweight meeting.  Except for drug testing, the camps have settled every significant detail of the fight, according to Arum and Golden Boy CEO Richard Schaefer.