* Ten-, 30-year debt post biggest price gains
* Surprisingly strong U.S. productivity data shrugged off
NEW YORK, Aug 8 (Reuters) - U.S. Treasuries climbed again on Friday, leaving benchmark yields at 14-month lows, amid a sell-off in global equities markets after President Barack Obama ordered targeted air strikes in Iraq.
The air strikes fueled investor anxieties already heightened by the Ukraine crisis, tit-for-tat economic sanctions between Russia and the West, and Argentina's unresolved debt default.
Fighting also resumed in Gaza between Palestinian militants and Israel.
Benchmark Treasury 10-year notes, whose yields were topping 2.50 percent on Tuesday, were up 9/32 in price in early New York trade and were yielding 2.3951 percent.
Earlier, the issue yielded 2.349 percent, a level last seen during June, 2013, according to Reuters data.
"It's a big flight to quality trade," said Charles Comiskey, head of Treasury trading for Scotia Bank in New York. "It's a rudderless, leaderless world everywhere. There is a lot of fear, and the fear is driving people to the Treasury market."
Thirty-year Treasury bonds also rose again, up 13/32 in price to yield 3.212 percent. The long bond on Friday had yielded as little as 3.178 percent, its lowest since June 2013.
Price gains in shorter maturities were smaller.
With investors focused on geopolitical matters, Treasuries trading is little affected by economic data, strategist and portfolio managers say.
On Friday, price gains pulled back only briefly on better-than-forecast data showing a 2.5 percent increase in U.S. productivity growth during the second-quarter. The report bolsters arguments Federal Reserve policymakers will raise interest rates sooner than investors believe.
"I don't think you have any fundamentals behind it," Comiskey said of this week's rally in Treasuries. "With our economy the way it is and Fed policies, I don't think you can make a case that we really should be here."
(Editing by W Simon)