LOS ANGELES, March 12 (Reuters) - The busiest U.S. container seaport in Los Angeles is mostly insulated from supply chain upheaval sparked by U.S.-Israel attacks on Iran that have spiraled into a regional conflict, its executive director Gene Seroka said on Thursday.

The Iran war has snarled container shipping in the Middle East, sending up costs, stranding ships and cargoes, threatening fuel shortages and endangering vessels and the lives of seafarers.

"We, right now, don't see any of that congestion happening" on the lucrative transpacific ocean trade that is the lifeblood of the Port of Los Angeles, Seroka said.

China and Asia are vital trading partners for the Port of Los Angeles. Most of the 40 container ship services at the Port of Los Angeles follow direct routes and are unconnected to the Middle East trade, Seroka said.

Beyond that, he said, manufacturing flows serving the United States, Europe and Latin America are continuing to move. 

Port data released Thursday showed a 5% rise in closely watched imports for February versus a year ago, after retailers and manufacturers brought in cargo ahead of the Lunar New Year holiday, when many factories in Asia close for celebrations. 

Total volume for the month of February hit the second-highest level in port history, Seroka said, after the Southern California trade gateway also handled almost 7% more exports than the year earlier.

In all, the Port of Los Angeles handled a total of 824,323 20-foot equivalent units (TEUs) in February including 433,812 TEUs of imports and 116,633 TEUs of exports and 273,878 TEUs of empty containers, according to port data. A TEU is a standard measurement of volume for ocean cargo. A typical shipping container is 40 feet. 

The port, a vital regional economic engine, is heading into its traditional slack season. Seroka expects first-quarter port volume to be down in the mid-single-digit percentages versus the period last year, when importers were rushing in goods to beat new tariffs going into effect.

"It will be followed by some replenishment of inventories, particularly spring and summer fashion," he said, noting that uncertainty from the Iran war or any other economic reason thus far has not caused U.S. importers to cancel purchase orders for seasonal apparel.

"That's a very good sign," Seroka said.