Seven more horses trained by banned Godolphin trainer Mahmood Al Zarooni, including 2012 St Leger winner Encke, have tested positive for anabolic steroid stanozolol.
The British Horseracing Authority said in a statement that the new cases arose during tests carried out after Al Zarooni was handed an eight-year ban by the BHA last month.
He was found responsible for doping horses with anabolic steroids after 11 tested positive at his stable in Newmarket, England but Al Zarooni has appealed against the severity of the ban.
Between April 29 and May 2, blood samples were taken from 391 horses and sent for analysis, the BHA said.
It added that analysis of the samples from horses based at Moulton Paddocks identified seven further positive tests for stanozolol, an anabolic steroid and therefore a prohibited substance under the Rules of Racing.
All of the horses under the care and control of Saeed bin Suroor tested negative, the BHA statement stressed.
As well as Encke, horses that test positive were Energizer, Genius Beast, Improvisation, Stamford, Steeler and Zip Top.
The seven horses will be suspended from running in Britain for a period of six months from the date the samples were taken.
The BHA has also notified Godolphin that the application for Saeed bin Suroor to take charge of Moulton Paddocks will now be processed.
Adam Brickell, director of Integrity, Legal and Risk for the BHA, said: "We will not be taking any separate action in respect of these additional positive results whilst Mr Al Zarooni's appeal process is on-going.
“In the meantime, the latest findings from HFL Sport Science will form the subject of further interviews as part of the BHA’s continuing investigation.”
Paul Bittar, chief executive of BHA, added: "These test results endorse the swift action and measures taken by the BHA in this matter. Whatever the outcome of his appeal before the independent Appeal Board, the gravity and scale of the infringements warranted Mahmood Al Zarooni being removed from control of the yard as quickly as possible.
"We welcome the news that Saeed bin Suroor's horses tested negative and this clears the way for him to now take charge of Moulton Paddocks."