The five Chinese naval ships spotted in the Bering Sea off Alaska coast have begun their return journey, The U.S. Navy said Friday.

"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 on Friday.

The return transit ends a first and rare visit of Chinese Navy ships to the Bering Sea. The five vessels included three warships, an amphibious ship and a replenishment ship.

The Pentagon confirmed Wednesday that they spotted five Chinese naval ships, including three warships, in Bering Sea off the coast of Alaska, as previously reported by HNGN. It was the first time that the Chinese Navy ships were spotted in the Bering Sea.

However, the Pentagon has downplayed the sighting of Chinese ships so close to its territorial waters. "We respect the freedom of all nations to operate military vessels in international waters in accordance with international law," the Pentagon spokesman Capt. Jeff Davis said on Wednesday, according to Russia Today.

China called the presence of its ships in the Bering Sea a "routine exercise." "This is a routine arrangement as part of annual plans, and is not aimed at any set country or goal," Chinese Defence Ministry said in a statement on Thursday, according to the Daily Mail.

Asian Defence analysts believed that the Bering visit of Chinese vessels was aimed to send a message to the U.S.

"By sailing the Bering Sea, the PLA Navy is [showing] the US [it] is capable of reaching these waters," Su Guan-chiun, a Taipei-based military commentator, told South China Morning Post.