Orders to US factories for durable goods rose unexpectedly in April, primarily due to a jump in defense orders, but a category that signals business investment plans fell by the biggest amount in three months, the government reported Tuesday, dimming hopes of a sharp rebound in economic growth in the second quarter. The Commerce Department said orders for durable goods - expensive manufactured items expected to last at least three years - rose 0.8 percent last month after a 3.6 percent jump in March and a 2.6 percent advance in February. Economists had expected durable-goods orders to decline 0.5 percent in April. The strength in April resulted from a big increase in demand for defense items including airplanes. Orders for defense capital goods soared 39.3 percent, the biggest gain since late 2012. Excluding defense, durable-goods orders actually fell 0.8 percent last month. Orders for transportation equipment rose 2.3 percent last month, even as orders for civilian aircraft and automobiles dropped. Orders excluding transportation rose 0.1 percent after increasing 2.9 percent in March. Orders for core capital goods, a closely watched gauge of business spending plans, fell 1.2 percent in April after rising by 4.7 percent the previous month. Economists had expected orders for core capital goods to rise slightly last month. The report could cause economists to lower expectations for a sharp increase in growth in the April-June quarter after the economy weakened in the first three months of the year.