After a long and acrimonious dispute, Turkey has taken delivery of six Heron drone aircraft from Israel, expecting an additional four by the end of April.

The delayed delivery followed a fence-mending trip to Turkey that Israeli Defense Minister Ehud Barak took to in January in a bid to ease the fallout of a diplomatic tiff spanning from the late order and Ankara's criticism of Israeli policies toward the Palestinians.

Turkey awarded the lucrative contract five years ago, placing the order with Israel Aerospace Industries and Elbit. Both companies beat major U.S. competitors but the contract was bogged from the start with delays stemming from technical problems.

The contract deadline was initially set at 24-30 months. But both contracts missed the first deadline, breaching, also, a follow-up delivery date for the dispatch of four Herons last August.

With the deal dogged by problems, the Turkish government threatened to pull the plug on the order, saying it would seek financial damages from the Israeli contractors.

Last December, however, Ankara announced its intention to speed up the deal with a revised contract that resulted from Barak's visit a month later.

The order is estimated at $183 million, of which $50 million is set to go to Turkish Aerospace Industries and Aselsan. While the bulk of the project rests with IAI and Elbit, TAI is the Heron program's prime contractor.

Turkish Defense Minister Vecdi Gonul was purported by national media to have confirmed that Israel had provided training to Turkish military personnel who will operate the drones. Performance tests were also carried out in Turkey before military officials signed off on delivery of the aircraft from Israel.

The Heron drone is capable of flying at an altitude of 30,000 feet for about 30 hours. Its maximum operating range has been estimated to be 2,000 miles.

Major military forces around the globe have been increasing the use of UAVs for reconnaissance, surveillance and, at times, offensive purposes.

Muslim but secular, Turkey has had a strong history of military cooperation with Israel. It has also acted as an intermediary for the Jewish state with the Arab world. Yet the Heron dispute aggravated relations late last year, forcing senior Israeli officials to meet with high-level government officials to try and mend ties.

During Barak's visit, Gonul expressed hope that cooperation in arms projects between Turkey and Israel would continue regardless of the diplomatic fracas sparked by the Israeli siege of Gaza.

Turkey hasn't official announced where it plans to deploy the drones but it has been widely speculated that its military will use them in along the country's rugged frontiers with Iraq, near the southeast province of Batman.