Marcel Siem maintained his three-shot lead at the Hassan II Trophy in Morocco after a four-under-par 68 in his second round to further boost his Masters push.

Siem, who is hoping for a strong result at the Golf du Palais Royal in order to break into the world's top 50 ahead of the qualification cut-off for Augusta, made seven birdies and three bogeys on his way to 12 under overall.

However, the German failed to make any headway into that score after four birdies in his opening eight holes.

Indeed, he would have seen his lead cut to two shots by Finland's Mikko Ilonen and England's David Horsey had he not picked up a shot on the 409-yard ninth hole - his last. 

Horsey, a winner when the tournament was first staged in Agadir two years ago, was in joint second after a five-under-par round today.

The 27-year-old got off to a flying start when he birdied his first three holes and then picked up another stroke at the fifth, but a double bogey five at the eighth dropped him back.

He then picked up another four birdies and a bogey at the last on the back nine.

It was Pablo Larrazabal who enjoyed the best round of the day, however, as he surged up the leaderboard with an eventful 64.

Like Horsey, the Spaniard birdied his first three holes as well as the fifth, sixth and ninth but saw his score falter with birdies at the fourth and seventh holes.

His back nine was a rather more sedate affair, although he still picked up another four shots to move onto eight under overall.

Scotland's Craig Lee, Bernd Wiesberger of Austria and Norway's Andreas Harto were tied for fifth two shots further back, while Joost Luiten was on four under.

Michael Hoey is the best of the Irish on three under after a 69, while Gareth Maybin is a shot further back after a 70.