CROW VALLEY, Tarlac - US aircraft dropped bombs and marines tore forward under artillery fire in war games in the Philippines on Thursday, weeks after the allies signed a defense deal against a backdrop of flaring Chinese tensions with its neighbors.

The live rounds made a dull thud and kicked up dust as they rained down on a dry riverbed at the start of the hour-long maneuvers, involving about 100 American and 200 Filipino marines.