U.S. government-to-government arms sales are growing fast and will likely exceed the bullish estimate of $40 billion for 2009, the Pentagon's top arms sales official said on Wednesday at the Paris Air Show. Vice Admiral Jeffrey Wieringa, head of the Pentagon's Defense Security Cooperation Agency, told Reuters it was unclear if arms sales would keep rising, but noted that was possible since several large weapons competitions were underway, and many countries had aging equipment to replace. Arms sales were at a "pretty unprecendented level" after averaging $8 billion to $13 billion per year in the early 2000s, Wieringa said. Sales in the first half reached $27 billion, some 60 percent of the year's expected total, making it likely the actual 2009 total would top $40 billion, he said. Wieringa said the Obama administration was committed to building international partnerships, and arms sales were an important instrument of that policy. "We sell stuff to build relationships," he said, noting that U.S. partners needed the right equipment and training to carry out their security missions. Brigadier General David Heinz, who heads the Pentagon's F-35 program, told that development and testing of the new fighter jet was going well, and that 6,000 of the new fighter jets could be sold over time as world fleets of F-15, F-16, F-18 and other fighter jets need replacements.