Iraq has signed an agreement with the United States to buy 18 F-16s and has already made an initial payment as part of the deal, Iraqi and American officials said on Tuesday. \"Iraq has signed with Washington to buy the F-16s,\" Ali Mussawi, media advisor to Prime Minister Nuri al-Maliki, told AFP.\"This agreement, for which Iraq has already paid some of the money, is for 18 F-16s in the first phase.\" He did not give details on a potential delivery date, or how much of an initial payment Iraq had made, but the Wall Street Journal reported that Baghdad had transferred $1.5 billion, citing officials in Washington. Pentagon spokesman George Little confirmed the deal and said the \"total value (of the sale) is approximately $3 billion,\" but did not specify the amount of the first payment. Iraq and the US had been close to reaching a deal on the fighter jets earlier this year, but Baghdad re-routed $900 million earmarked for the purchase to a welfare programme amid nationwide protests. Maliki said this summer that Iraq was looking at the purchase of 36 jets, rather than the previously mooted 18.Any deal would be worth billions of dollars and take years to implement, as it would require the manufacture of the aircraft and the training of Iraqi pilots. The F-16 has been exported to more than 20 countries. Ten Iraqi pilots are already training on the fighter in the United States and their instruction could be completed before the delivery of the first planes to Baghdad, General Russ Handy, head of the US air forces in Iraq, said on September 14. US and Iraqi commanders have said that while they believe Iraq\'s forces to be capable of maintaining internal security, the country still lacks the capacity to defend its borders, air space and territorial waters.