Birmingham, June 7 (IANS): Double Olympic champion Mo Farah announced he was pulling out of the Birmingham Diamond League athletics championships just hours before the meet kicks off at the Alexander Stadium here.

"This week has been very stressful and taken a lot out of me," he said in the statement on Sunday, reports Xinhua.

"I have not been able to focus properly on Sunday's race, and after the events of the last few days feel emotionally and physically drained," he said.

"I want to run well in the IAAF World Athletics Championships in Beijing and have decided it is better for me to go back to the US, seek answers to my questions and get back into training."

"I apologise to the people who bought tickets to come and watch me race and ask for your understanding at this time," he added.

The 32-year-old has been angry after his name was linked with "doping scandals" recently.

It was alleged his coach Alberto Salazar had been involved in doping by giving banned drugs to US 10,000m record holder Galen Rupp in 2002 when the athlete was 16 years old.

Rupp is still Farah's training partner.

Farah, who won 5,000 metres and 10,000 metres gold at the 2012 London Olympics, said on Saturday that the allegations against his coach had affected his preparation for Sunday's race.

"My reputation is getting ruined. You guys are killing me," he said.

"I'm a clean athlete. I'm against drugs 100 percent and believe anyone caught should be banned for life."