SOMALIA’S president has shielded a top pirate leader from arrest by issuing him a diplomatic passport, according to a United Nations investigation which criticises the "climate of impunity” enjoyed by pirate kingpins in Somalia and abroad.The U.N. Monitoring Group on Somalia said in a report to the Security Council, seen by Reuters, that senior pirate leaders were benefitting from high level protection from Somali authorities and were not being sufficiently targeted for arrest or sanction by international authorities.The Group said it had obtained evidence a diplomatic passport had been provided "with the authorization of Somali President Sheikh Sharif Sheikh Ahmed” to pirate leader Mohamed Abdi Hassan "Afweyne”, who presented it to authorities in Malaysia on a trip there in April.Questioned by Malaysian immigration, Afweyne provided a document issued by the Somali presidency stating he was involved in counter-piracy activities, the report said. It said that Somalia’s President Ahmed had told the Group the passport was "one of several inducements” for Afweyne aimed at obtaining the dismantling of his pirate network.In a July 12 letter to the Chairman of the Security Council’s Sanctions Committee, obtained by Reuters, Ahmed called the contents of the Monitoring Group’s report "one-sided”.The letter said the principal author of the U.N. report, whom it did not name, "seems hell bent on soiling the good names of private members of the Somali people by throwing at them unsubstantiated allegations”.Somali government officials in Mogadishu could not be reached for comment.The U.N. report has also riled the authorities in the semi-autonomous region of Puntland, who are criticised for failing to arrest well-known senior pirate leaders, in spite of a counter-piracy campaign that has reportedly resulted in the arrest of hundreds of low-level pirates.The report said that only one Puntland based pirate leader, Abshir Boyah, had been arrested by the Puntland authorities but said his jail sentence of only five years contrasted sharply with terms of up to 20 years given to junior pirate figures.Agencies