Platanillo-3 Update

6 June 2012

Amerisur Resources Plc ("Amerisur" or the "Company")

Platanillo-3 Update

·; The Platanillo-3 well encountered an interval of 85ft gross, 52ft net pay in the U sands of the Villeta formation

·; Platanillo-3 flowed 30.4°API oil with trace water at 2,340 BOPD in natural flow

·; The Company plans to skid the Serinco Rig D-10 and drill the second well of the current programme from the same location (Platform 9), deviating the well to an offset of approximately 600m south of Platanillo-3.

Amerisur Resources Plc, the oil and gas producer and explorer focused on South America, is pleased to announce an update on the well Platanillo-3 in the Platanillo Field, Colombia, the first of a planned six well drilling campaign.

After analysis of the electric logs the Company has estimated that the Platanillo-3 well encountered an interval of 85ft gross, 52ft net pay in the U sands of the Villeta formation. Two additional zones within the Villeta may also contain potential pay and are under evaluation.

The Company perforated the upper 26ft of indicated net pay using a Drill Stem Testing assembly. Over a flow period of 24 hours the interval produced in natural flow at a final stabilised rate of approximately 2,340 BOPD of 30.4° API oil with trace water, while choked back and with wellhead pressure of approximately 44 psi.

The well has now been closed in to perform a pressure build up (PBU) test, in order to acquire pertinent reservoir pressure information. Once the PBU is completed the Company plans to install a permanent completion string and commence commercial production from the well. Given the high productivity of the well, Amerisur is evaluating completion options to maximise efficiency, including the installation of a downhole electrical pumping system.

With these excellent results from Platanillo-3 the Company plans to skid the Serinco Rig D-10 and drill the second well of the current programme from the same location (Platform 9), deviating the well to an offset of approximately 600m south of Platanillo-3.

John Wardle, Amerisur Chief Executive commented: "This is an impressive result which underlines the potential of the Platanillo field. Our objective now is to push forward with the next wells, optimising their costs and operational efficiency to deliver our production targets this year."

Giles Clarke, Chairman of Amerisur said: "I would like to congratulate our CEO John Wardle and all staff and contractors who have been working under extremely arduous conditions. The geological analysis performed by Dr Wardle and his colleagues has been fully vindicated. The Board looks forward to more exciting developments of this field."

ENDS

Competent person: Technical information in this announcement has been reviewed by John Wardle Ph.D., the Company's Chief Executive. John Wardle has 27 years' experience in the industry, having worked for BP, Britoil, Emerald Energy and Pebercan, and is a trained drilling engineer.

ENQUIRIES: