The swap of prisoners agreed upon Tuesday between Israel and Hezbollah was mediated over an 18-month period by a German secret agent, according to sources in the German capital Berlin on Tuesday, according to dpa. German involvement had been reported all along in the Middle East, but never confirmed by Berlin. Quoting an internal document compiled by Chancellor Angela Merkel's office, the sources said the "facilitator" was a staffer with the BND, the German foreign intelligence agency, who was authorized by the United Nations to manage the secret contacts. Over the 18 months, he flew a total of 700,000 kilometres, shuttling between UN headquarters in New York, Tel Aviv, Beirut and various European capitals. The deal is set to come to fruition on Wednesday morning at Rosh Ha'Nikra/Naquora, the only border crossing between Israel and Lebanon, with the handover of two Israeli soldiers, Eldad Regev and Ehud Goldwasser, who are presumed to be dead. They were seized in July 2006. Five Lebanese prisoners are set to be released in the swap, which the Berlin document said was the fruit of "extraordinarily difficult" negotiations. It calls the deal a "great success" for the UN, the German government and the "excellent" German mediator himself. The paper does not name the mediator, but Middle East news reports have regularly identified him as Gerhard Conrad, a BND officer who was assigned to broker the previous Israel-Hezbollah prisoner swap in 2004. He is respected and trusted by both sides and by the UN. The document notes that the negotiated swap is not the end of BND mediation, since Germany has promised Israel continuing assistance in finding out what happened to other missing Israeli personnel, as has already been provided for the past 15 years. However the German programme apparently does not extend to the case of Gilad Shilat, the Israeli soldier kidnapped two years ago by the Hamas movement which controls the Gaza Strip, the sources said.