(Sharecast News) - Shares in Anglo African Oil and Gas tumbled in early trade after the firm announced the temporary suspension of drilling at one of its Tilapia oil field assets in the Republic of the Congo.The independent oil and gas developer was informed by SMP on Wednesday that the drilling contractor had experienced a topside issue that had affected the rig.As a result, Anglo African decided to temporarily suspend drilling at the TLP-103 well while a specialist review of the various solutions was undertaken.Anglo African said it was working to determine the optimum solution in order to restrict the delay to "a matter of weeks" and claimed it was putting in place contingencies aimed at recovering costs and any overruns.As of 0845 BST, Anglo African shares had tumbled 23.08% to 9p.