Welsh athletes Rhys Williams and Gareth Warburton have insisted that they are focused on returning to competitive action after serving bans for doping.

Williams, who is a 400m hurdles European champion, was banned for four months, while 800m runner Warburton was forced to miss six months of action.

The UK National Anti-Doping Panel implemented the suspensions, but both sportsmen were found not guilty of intentionally cheating.

On Sunday, Williams released a statement, which read: "I carried out all necessary checks within my power before consuming the product, unfortunately in this instance I have been severely let down by a manufacturing company.

"However, I accept that responsibility for the supplements I take rests with me and I accept the four-month ban. I remain as committed to drug free athletics as ever.

"I am looking forward to getting back on to the track, with my focus now firmly on gaining selection for the World Championships in 2015."

In a separate statement, Warburton said: "Unfortunately, I have simply been an unlucky victim of a contaminated supplement, but I do take full responsibility for all substances found in my system.

"As a passionate Welshman, missing out on the chance to represent my country at last year's Commonwealth Games was devastating.

"However, I am now looking forward to putting this difficult period behind me and getting back to what I love doing."

Metabolites of a designer anabolic steroid were found in their systems.