May container cargo movement at the Port of Long Beach reached its highest level since October, officials reported Wednesday.

Cargo traffic at the port increased by 6 percent to 635,250 containers last month compared to a year ago, marking the third consecutive month of steady growth. Imported container volume rose 4.8 percent from the year-ago period to more than 327,300 containers, while the roughly 135,850 exported containers was off 7.4 percent. Empty containers returned to overseas ports rose 22.6 percent to more than 172,000 containers.

Port officials cited a stronger retail market and new services offered by the port as factors driving the growth. Year-to-date container cargo movement has grown 1.1 percent over the same period a year ago.

Earlier this week, the Port of Los Angeles reported container cargo movement was up 0.8 percent in May compared to the year-ago period, due to a large volume of empty containers heading back overseas. Container cargo movement was down 4 percent for the first five months of the year compared to the same period last year. May numbers improved from April when container cargo volume was off 6.1 percent from the year earlier.