U.S. import prices unexpectedly fell in June as the lingering effects of a strong dollar offset rising costs for petroleum products, keeping imported inflation pressure under wraps.

The Labor Department said on Tuesday import prices dipped 0.1 percent last month after a downwardly revised 1.2 percent increase in May.

Import prices have now declined in 11 of the last 12 months. Economists had forecast import prices edging up 0.1 percent after a previously reported 1.3 percent jump in May. In the 12 months through June prices fell 10.0 percent.

Last month, imported petroleum prices rose 0.8 percent after surging 11.7 percent in May.

Import prices excluding petroleum slipped 0.2 percent after being unchanged in May, reflecting dollar strength. The dollar has gained 11.6 percent against the currencies of the United States' main trading partners since June 2014 on expectations the Federal Reserve will raise interest rates this year.

Last month, imported food prices fell 0.6 percent after rising 0.2 percent in May. Prices for imported capital goods were unchanged, while automobiles fell 0.1 percent.

The report also showed export prices fell 0.2 percent last month after rising 0.6 percent in May. Export prices dropped 5.7 percent in the 12 months through June.