The Chinese navy holds a memorial ceremony for the 120th anniversary of the first Sino-Japanese War, Aug. 27, 2014, in Weihai, China. Getty Images

The five Chinese navy ships that were spotted in the Bering Sea off Alaska this week came within 12 nautical miles of the U.S. coastline, the Wall Street Journal reported Friday. The ships complied with international law and did not appear to be threatening.

"They already had one of their icebreakers up in that area, and they weren't that far away with an exercise, and they've already started their return transit," Chief of Naval Operations Admiral Jonathan Greenert told Reuters.

The Chinese vessels were spotted off Alaska on Wednesday, when President Barack Obama was in the state conducting a three-day tour highlighting climate change. Although U.S. officials have emphasized that Russian warships often exercise “innocent passage” around Alaska, this was the first time Chinese navy ships have done so, CNN reported. The deployment was seen as significant because Beijing has consistently objected to U.S. Navy vessels passing through its territorial waters.

While the ships did not seem to engage in any threatening activity, White House press secretary Josh Earnest told reporters Wednesday that the intent of the deployment was unclear.

Sailors with the Peoples' Liberation Army Navy (PLAN) of China march at the Ngong Shuen Chau barracks during Hong Kong's Special Administrative Region Establishment Day holiday, July 1, 2015. Getty Images