(CNN) China's lone aircraft carrier is prowling the Pacific as the country seeks to assert its military might and build up its naval warfare capabilities.

The Liaoning carrier's J-15 fighter jets practiced air confrontations and air refueling in the Yellow Sea late last week before the ship and its flotilla of escorting frigates and destroyers headed into the open Pacific beyond Taiwan and Okinawa.

On Monday it headed to the South China Sea -- the site of regional tensions caused by China building fortifications on disputed islands

It's a move that hasn't gone unnoticed by China's Asian neighbors.

Taiwan sounded a note of alarm, with its defense minister emphasizing the need for vigilance.

Chinese J-15 fighter jets wait on the deck of the Liaoning aircraft carrier during military drills in December.

"The threat of our enemy is growing day by day. We should always be maintaining our combat alertness," said Taiwan Defense Minister Feng Shih-Kuan.

Japan's Defense Ministry, meanwhile, said it's the first time it could confirm the Liaoning, which China bought from Ukraine in 1998, then rebuilt and commissioned in 2012 as a training vessel, had gone into the open Pacific.

"We are taking notice of this event, which indicates China is expanding its ability to engage in maritime warfare," Japanese Chief Cabinet Secretary Yoshihide Suga said.

And it looks like that's exactly the point China's trying to make clear.

A warning for Eastern Pacific

China's state-run Global Times media agency published an editorial on Christmas Day, timed to coincide with the aircraft carrier Liaoning's maneuvers.

The piece called on China to build up its fleet of aircraft carriers, make them combat ready, sail them to Eastern Pacific and look to set up naval supply bases in South America.

The Global Times also said the drill is a sign the Liaoning's combat capability has been enhanced and its areas of operation expanded, and could soon include the Eastern Pacific, including off the US West Coast.

"When China's aircraft carrier fleet appears in offshore areas of the US one day, it will trigger intense thinking about maritime rules.

"If the fleet is able to enter areas where the US has core interests, the situation when the US unilaterally imposes pressure on China will change," the Global Times said.

The editorial called on China to speed up construction of homemade aircraft carriers "so as to activate their combat."

China is believed to have one new carrier near completion and another about to start construction, said Carl Schuster, a professor at Hawaii Pacific University and former director of operations at the US Pacific Command's Joint Intelligence Center.

But China's ability to pose a long-range threat with aircraft carriers is a long way off, he said.

A difficult buildup for China

"China has no corps of experienced naval aviators and aircraft carrier crewmen on which to build their carrier force," Schuster said in an email to CNN. "They are having to build it from scratch ... a difficult challenge for a force reliant on 2-year conscripts for most of its personnel."

Schuster said China is planning for a fleet of four carriers by 2027-2029.

Even with the additional carriers, its carrier fleet will only be less than half the size of that of the US Navy, which boasts 10 carriers in service, another near commissioning and another under construction.

Photos: US aircraft carriers Photos: US aircraft carriers Sailors spell out #USA with the American flag on the flight deck of the Nimitz-class aircraft carrier USS Theodore Roosevelt in the Persian Gulf in late June 2015. When the Roosevelt leaves the Gulf sometime in October, the U.S. Navy will be without a carrier in the important region for two months. Hide Caption 1 of 31 Photos: US aircraft carriers A MV-22B Osprey, from Marine Operational Test and Evaluation Squadron 1, lifts off from the flight deck of the aircraft carrier USS Carl Vinson (CVN 70) on June 12, 2016. Click through the gallery to see other US aircraft carriers. Hide Caption 2 of 31 Photos: US aircraft carriers Tug boats maneuver the aircraft carrier Pre-Commissioning Unit Gerald R. Ford (CVN 78) into the James River during the ship's turn ship evolution on June 11, 2016. This is a major milestone that brings the country's newest aircraft carrier another step closer to delivery and commissioning later this year. Hide Caption 3 of 31 Photos: US aircraft carriers The Nimitz-class aircraft carrier USS Ronald Reagan (CVN 76) arrives at the U.S. Navy base in Yokosuka, a suburb of Tokyo, Japan, on October 1, 2015. The Reagan is the fifth U.S. carrier forward deployed to Japan following USS George Washington (CVN 73), USS Kitty Hawk (CV 63), USS Independence (CV 62) and USS Midway (CV 41), according to the Navy. Hide Caption 4 of 31 Photos: US aircraft carriers The aircraft carrier USS Dwight D. Eisenhower (CVN 69) (Ike) transits through the Strait of Gibraltar into the Mediterranean Sea on June 13, 2016. Ike, the flagship of the Eisenhower Carrier Strike Group, is conducting naval operations in the U.S. 6th Fleet area of operations. It could be used to support operations against ISIS in the Mideast. Hide Caption 5 of 31 Photos: US aircraft carriers A rainbow forms over the bow of the Nimitz-class aircraft carrier USS John C. Stennis as the ship steams in the Pacific Ocean on February 3, 2015. Hide Caption 6 of 31 Photos: US aircraft carriers U.S. aircraft carrier classes – U.S. Secretary of Defense Ash Carter (left) and Philippine Secretary of National Defense Voltaire Gazmin shake hands on a Marine Corps V-22 Osprey as they depart the the aircraft carrier USS John C. Stennis (CVN 74) after touring the aircraft carrier as it sailed in the South China Sea on April 15, 2016. Hide Caption 7 of 31 Photos: US aircraft carriers A photo illustration of the U.S. Navy's Gerald R. Ford-class aircraft carrier USS John F. Kennedy (CVN-79). The ship's keel laying ceremony was celebrated Saturday, August 22, 2015, in Newport News, Virginia. The ship is expected to replace the USS Nimitz (CVN-68), scheduled for inactivation in 2025, in the Navy fleet. The newest Kennedy will be the second carrier of that name. The first John F. Kennedy (CVA-67) was the last conventionally powered carrier. It was decommissioned in 2007. Hide Caption 8 of 31 Photos: US aircraft carriers The aircraft carrier USS Harry S. Truman (CVN 75) passes under the Friendship Bridge while transiting the Suez Canal on Dec. 14, 2015. The ship is conducting operations in the Persian Gulf, where Iran claims to have taken footage of the carrier using a drone. Click through the gallery for more images of U.S. Navy aircraft carriers. Hide Caption 9 of 31 Photos: US aircraft carriers Aviation Structural Mechanic Airman V. Sek, assigned to the "Jolly Rogers" of Strike Fighter Squadron (VFA) 103, applies a Christmas decal to an F/A-18F Super Hornet in the hangar bay of the Nimitz-class aircraft carrier USS Harry S. Truman in December 2015. Hide Caption 10 of 31 Photos: US aircraft carriers The Nimitz-class aircraft carrier USS George Washington (CVN 73) is seen from inside its sister ship, the USS Ronald Reagan (CVN 76), on August 7 off the coast of California as the two ships prepare for a "hull swap." Over 10 days in San Diego, much of the crew of each ship will transfer to the other. When completed, the Reagan will head to forward deployment in Japan, where the Washington had been. The Washington will head to Newport News, Virginia, for an overhaul. Hide Caption 11 of 31 Photos: US aircraft carriers Three Nimitz-class aircraft carriers USS Carl Vinson (CVN 70), top, USS Ronald Reagan (CVN 76), center, and USS John C. Stennis (CVN 74) are pierside at Naval Air Station North Island near San Diego on June 12, 2015. The Vinson has just recently returned from a 10-month deployment. The Reagan is preparing for a move to Japan later this year and the Stennis was making a port call after steaming from its homeport of Bremerton, Washington. Hide Caption 12 of 31 Photos: US aircraft carriers Sailors test the countermeasure washdown system on the flight deck of the Nimitz-class aircraft carrier USS Dwight D. Eisenhower (CVN 69) during sea trials prior to returning to its homeport at Naval Station Norfolk in late August 2015. Hide Caption 13 of 31 Photos: US aircraft carriers The aircraft carrier USS Theodore Roosevelt departs Naval Station Norfolk, Virginia, on Wednesday, March 11, for a scheduled deployment. The Nimitz-class carrier's departure was delayed for two days after marine growth clogged sea water intakes. Divers went into the 36-degree water to clean out the intakes and allow the ship to get under way. The cold water created a fog that made it seem the ship was in a cloud. Hide Caption 14 of 31 Photos: US aircraft carriers The USS Abraham Lincoln, a Nimitz-class aircraft carrier, is seen near the coast of Indonesia in 2005. The carrier recently received a new anchor from the decommissioned USS Enterprise. Hide Caption 15 of 31 Photos: US aircraft carriers Lightning strikes over the flight deck of the USS John C. Stennis, another Nimitz-class aircraft carrier, as the ship moves through the Persian Gulf in 2007. All of the Navy's 10 active aircraft carriers are from the Nimitz class, which started in 1975 with the commission of the USS Nimitz. Hide Caption 16 of 31 Photos: US aircraft carriers The USS Ranger (CV-61) arrives at Pearl Harbor, Hawaii, in 1993. The Forrestal-class carrier, which featured in the movie "Top Gun," is to be scrapped this year. Hide Caption 17 of 31 Photos: US aircraft carriers In this photo released by the U.S. Navy, a tugboat works alongside the decommissioned aircraft carrier USS Saratoga on Thursday, August 21, in Newport, Rhode Island. The Navy has paid a Texas recycling company a penny to dispose of the Saratoga, part of the Forrestal-class of "supercarrier" vessels built for the Atomic Age. The carrier was decommissioned 20 years ago. Hide Caption 18 of 31 Photos: US aircraft carriers Aircrew members are lifted from the flight deck of the USS John F. Kennedy during an exercise in 2002. The ship, which was decommissioned in 2007, was the only member of its class. Hide Caption 19 of 31 Photos: US aircraft carriers An F/A-18 Hornet launches from the USS Enterprise in 2007. The Enterprise, the world's first nuclear-powered aircraft carrier, was decommissioned in 2012. Like the John F. Kennedy, it was the only ship built in its class. Hide Caption 20 of 31 Photos: US aircraft carriers The Kitty Hawk class was named for the USS Kitty Hawk, seen here departing Yokosuka, Japan, in 2008. At that time, the Kitty Hawk was the oldest carrier in the U.S. Navy and the only conventional-power aircraft carrier still in commission. It was decommissioned in 2009. Hide Caption 21 of 31 Photos: US aircraft carriers The USS Independence, a member of the Forrestal class that preceded the Kitty Hawk class, heads up the East River in New York in 1959. Hide Caption 22 of 31 Photos: US aircraft carriers Helicopters sit on the flight deck of the USS Saipan during the mid-1950s. The ship was one of two members of the Saipan class. Hide Caption 23 of 31 Photos: US aircraft carriers The USS Midway, namesake of the Midway class of aircraft carriers, floats off the coast of North Vietnam in 1972. It was named after the Battle of Midway, when U.S. forces held back a Japanese attempt to take the Pacific atoll in 1942. Hide Caption 24 of 31 Photos: US aircraft carriers The USS Princeton, part of the Independence class, moves off the coast of Seattle in 1944. Hide Caption 25 of 31 Photos: US aircraft carriers The Essex-class USS Franklin burns after being hit by a Japanese dive bomber in 1945. The ship was named after Benjamin Franklin and nicknamed "Big Ben." Hide Caption 26 of 31 Photos: US aircraft carriers The USS Wasp burns in the Coral Sea after being struck by three torpedoes from a Japanese submarine in 1942. The ship, the only one of its class, would ultimately sink because of the damage. Hide Caption 27 of 31 Photos: US aircraft carriers B-25 bombers sit on the deck of the USS Hornet in the Pacific Ocean in 1942. The Hornet, one of three carriers in the Yorktown class, was the ship that launched the bombers flown by Air Force Lt. Col. James Doolittle and his pilots during an air raid in Tokyo four months after the attack on Pearl Harbor. It also was involved in the Battle of Midway. Hide Caption 28 of 31 Photos: US aircraft carriers Navy personnel work on board the USS Ranger circa 1942. The Ranger was the first ship to be designed and built specifically as an aircraft carrier. It was the only ship in its class. Hide Caption 29 of 31 Photos: US aircraft carriers There have actually been two aircraft carriers named after the Revolutionary War's Battle of Saratoga. The first USS Saratoga, seen here moving toward San Francisco's Golden Gate Bridge in 1945, was one of two members of the Lexington class of aircraft carriers. Hide Caption 30 of 31 Photos: US aircraft carriers The USS Langley, the Navy's first aircraft carrier and sole member of its class, steams off the coast of Baltimore in 1924. Hide Caption 31 of 31

For now, though, the Global Times is pushing China to project power beyond the "first string" of islands around the country; an arc stretching from north of the Paracel Islands group in the South China Sea, northeastward to encompass Taiwan, west of Okinawa and north into the East China Sea between the Koreas and China.

"As China's only aircraft carrier fleet now, it should have the ability and courage to sail farther," it said, "...to the waters where Chinese ... fleets have never been."

And that would encompass waters of the Eastern Pacific.