Danang, Vietnam(CNN) For the first time since the end of the Vietnam War more than four decades ago, a US Navy aircraft carrier has arrived in the country.

The USS Carl Vinson anchored two nautical miles off the port city of Danang, which was a key battleground during the war that ended in 1975.

"Our nations' relationship has reached new heights in the past few years, and the USS Carl Vinson's port visit to Vietnam is a reflection of that," said US Pacific Fleet Commander Adm. Scott Swift.

Publicly, the United States has portrayed the four-day visit by the Vinson and its contingent of 5,000 sailors and aviators as a historic opportunity to enhance the budding friendship that has emerged between the two former foes.

But it's far from a standard port call.

Analysts say the visit by the 95,000-ton carrier to Vietnam is a clear shot at Beijing, designed to counter China's aggressive island building and militarization in the South China Sea.

The USS Mitscher is seen off the Vietnamese coast Monday.

"Vietnam has been deeply concerned about China's pugilistic and aggressive moves in the South China Sea," said John Kirby, a retired US Navy rear admiral and CNN military and diplomatic analyst.

"They are worried about where China is going, and they have wanted for years now to have a better relationship with the United States."

Cultural exchanges, including culinary and sporting activities, will take place between some of the US military personnel on board and their Vietnamese counterparts. Some US sailors will also visit a center for victims of Agent Orange, the toxic chemical compound used by the US during the conflict to destroy jungles and forests.

This aerial photograph of Johnson South Reef reef obtained by the Philippine Inquirer and taken on November 28, 2017, shows Chinese militarization and reclamation on the reef.

Island fortresses

The subject of China, and Chinese activity in the South China Sea, is likely to loom large over the visit.

Since 2014, China has forged ahead with island-building in the disputed waters, despite a landmark ruling in 2016 by the Permanent Court of Arbitration in The Hague, which said there was no legal basis for China's maritime claims.

China's claims to the South China Sea stretch roughly 1,000 miles from its southern shores, pitting it against Taiwan, the Philippines, Brunei, Malaysia, and Vietnam.

High-resolution aerial images of China's reclamation efforts in the Spratly Islands, recently obtained by the Philippine Inquirer newspaper, show that the reefs and sandbars have been turned into island fortresses, with ports, air strips, lighthouses, hangars and multi-story buildings.

Vietnam is among the claimants that has stood up most publicly against China, after the Philippines -- long one of most ardent critics of Chinese expansion in the area -- reversed course under President Rodrigo Duterte.

In June 2017, Vietnam refused Chinese demands to cease drilling on Vanguard Bank, an area that belongs to Vietnam under international law. Vietnam had granted a subsidiary of Spanish company Repsol drilling rights to the bank. China claims the area is part of its territory.

Vietnam eventually backed down a month later, under pressure from China.

Vietnam has also urged its fellow ASEAN nations to take a stronger stance against China in the South China Sea, though the body has largely chosen not to forcefully challenge Beijing.

"This is obviously a game of balance of power, and China is flexing its muscle in the South China Sea," said Le Hong Hiep, a fellow at Singapore's ISEAS Yusof Ishak Institute.

"Other countries will need to do more to counteract China."

US role

The United States has long had a robust naval presence in Southeast Asia, in part to ensure the openness of the South China Sea trading routes. Some $5 trillion in goods pass through those waters each year.

Under US President Donald Trump and his predecessor, President Barack Obama, the US has conducted "freedom of navigation" operations, sailing military vessels and flying planes close to islands China controls, often triggering heated warnings from Chinese patrols.

But it has done little to rein in China's expansionism in the South China Sea.

"The US does need to take a consistent and perhaps more assertive approach to how to deal with this advancement," said Kirby.

"I do not think it's too late to forestall further militarization, but I think we need to have a comprehensive -- and not just a military -- strategy for how to deal with this."

Iconic photos of the Vietnam War 1960s photojournalists showed the world some of the most dramatic moments of the Vietnam War through their camera lenses. LIFE magazine's Larry Burrows photographed wounded Marine Gunnery Sgt. Jeremiah Purdie, center, reaching toward a stricken soldier after a firefight south of the Demilitarized Zone in Vietnam in 1966. Commonly known as Reaching Out, Burrows shows us tenderness and terror all in one frame. According to LIFE, the magazine did not publish the picture until five years later to commemorate Burrows, who was killed with AP photographer Henri Huet and three other photographers in Laos. Associated Press photographer Nick Ut photographed terrified children running from the site of a Vietnam napalm attack in 1972. A South Vietnamese plane accidentally dropped napalm on its own troops and civilians. Nine-year-old Kim Phuc, center, ripped off her burning clothes while she ran. The image communicated the horrors of the war and contributed to growing U.S. anti-war sentiment. After taking the photograph, Ut took the children to a Saigon hospital. Eddie Adams photographed South Vietnamese police chief Gen. Nguyen Ngoc Loan killing Viet Cong suspect Nguyen Van Lem in Saigon in 1968. Adams later regretted the impact of the Pulitzer Prize-winning image, apologizing to Gen. Nguyen and his family. "I'm not saying what he did was right," Adams wrote in Time magazine , "but you have to put yourself in his position." A helicopter raises the body of an American paratrooper killed in action in the jungle near the Cambodian border in 1966. Henri Huet, a French war photographer covering the war for the Associated Press, captured some of the most influential images of the war. Huet died along with LIFE photographer Larry Burrows and three other photographers when their helicopter was shot down over Laos in 1971. Legendary Welsh war photographer Philip Jones Griffiths captured the battle for Saigon in 1968. U.S. policy in Vietnam was based on the premise that peasants driven into the towns and cities by the carpet-bombing of the countryside would be safe. Furthermore, removed from their traditional value system, they could be prepared for imposition of consumerism. This "restructuring" of society suffered a setback when, in 1968, death rained down on the urban enclaves. In 1971 Griffiths published "Vietnam Inc." and it became one of the most sought after photography books. Newly freed U.S. prisoner of war Air Force Lt. Col. Robert L. Stirm is greeted by his family at Travis Air Force Base in Fairfield, California, in 1973. This Pulitzer Prize-winning photograph, named Burst of Joy, was taken by Associated Press photographer Sal Veder. "You could feel the energy and the raw emotion in the air," Veder told Smithsonian Magazine in 2005. This 1965 photo by Horst Faas shows U.S. helicopters protecting South Vietnamese troops northwest of Saigon. As the Associated Press chief photographer for Southeast Asia from 1962-1974, Faas earned two Pulitzer Prizes. Oliver Noonan, a former photographer with the Boston Globe, captured this image of American soldiers listening to a radio broadcast in Vietnam in 1966. Noonan took leave from Boston to work in Vietnam for the Associated Press. He died when his helicopter was shot down near Da Nang in August 1969. In June 1963, photographer Malcolm Browne showed the world a shocking display of protest. A Buddhist monk named Thich Quang Duc burned himself to death on a street in Saigon to protest alleged persecution of Buddhists by the South Vietnamese government. The image won Browne the World Press Photo of the Year. Tim Page photographed a U.S. helicopter taking off from a clearing near Du Co SF camp in Vietnam in 1965. Wounded soldiers crouch in the dust of the departing helicopter. The military convoy was on its way to relieve the camp when it was ambushed. Frenchman Marc Riboud captured one of the most well-known anti-war images in 1967. Jan Rose Kasmir confronts National Guard troops outside the Pentagon during a protest march. The photo helped turn public opinion against the war. "She was just talking, trying to catch the eye of the soldiers, maybe try to have a dialogue with them," recalled Riboud in the April 2004 Smithsonian magazine, "I had the feeling the soldiers were more afraid of her than she was of the bayonets." In this 1965 Henri Huet photograph, Chaplain John McNamara administers last rites to photographer Dickey Chapelle in South Vietnam. Chapelle was covering a U.S. Marine unit near Chu Lai for the National Observer when a mine seriously wounded her and four Marines. Chappelle died en route to a hospital, the first American woman correspondent ever killed in action. Mary Ann Vecchio screams as she kneels over Jeffrey Miller's body during the deadly anti-war demonstration at Kent State University in 1970. Student photographer John Filo captured the Pulitzer Prize-winning image after Ohio National Guardsmen fired into a crowd of protesters, killing four students and wounding nine others. An editor manipulated a version of the image to remove the fence post above Vecchio's head, sparking controversy. For his dramatic photographs of the Vietnam War, United Press International staff photographer David Hume Kennerly won the 1972 Pulitzer Prize for feature photography. This 1971 photo from Kennerly's award-winning portfolio shows an American GI, his weapon drawn, cautiously moving over a devastated hill near Firebase Gladiator. Hubert Van Es, a Dutch photojournalist working at the offices of United Press International, took this photo on April 29, 1975, of a CIA employee helping evacuees onto an Air America helicopter. It became one of the best known images of the U.S. evacuation of Saigon. Van Es never received royalties for the UPI-owned photo. The rights are owned by Bill Gates through his company, Corbis. Associated Press photographer Art Greenspon captured this photo of soldiers aiding wounded comrades. The first sergeant of A Company, 101st Airborne Division, guided a medevac helicopter through the jungle to retrieve casualties near Hue in April 1968.

In Vietnam, the United States sees an opportunity to join forces over a common problem and push back against China's growing influence in Asia.

US military ties with Vietnam have deepened since 2016, when Obama lifted the decades-old embargo on US arms sales to the country as part of his Asia pivot.

Under Trump, military cooperation with Hanoi has continued.

Despite pulling the US out of the Trans-Pacific Partnership, a regional trade deal that Vietnam was a key part of, Trump has maintained strong ties with Hanoi.

In November, Trump visited Vietnam as part of his inaugural Asia trip aimed at reassuring allies that the US was still committed to the region, and in January, the US Defense Secretary James Mattis also visited, laying the groundwork for this week's visit by the USS Carl Vinson.

The frigate USS Vandegrift arrives November 19, 2003, in Ho Chi Minh City, Vietnam. The visit marked the first US Navy ship visit to Vietnam in 30 years, since 1973.

US message: We're here to stay

In addition to Vietnam, the US is also tightening military cooperation with long-standing allies Australia, Japan and India.

The nomination of Adm. Harry Harris, the highest commander of US forces inthe Asia Pacific region, as US ambassador to Australia is expected to further enhance cooperation between Canberra and Washington in issues relating to the South China Sea.

US warships have visited Vietnam several times since November 2003, when a US frigate, the USS Vandegrift, made the first port call to the country since the Vietnam War ended. However, a visit by an aircraft carrier is of a different level and something that government officials in Beijing will be paying close attention to.

On Friday, a Chinese Ministry of Foreign Affairs spokeswoman said that she hoped that the visit can "play a constructive role for the region instead of making the regional countries feel worried."

Kirby said the carrier's arrival in Vietnam sent a clear signal.

"It's a message to Vietnam, about how much we care about that relationship; it's a message to China, about what they're doing in the region; but it's also a broader message to everyone in the Pacific region, that the United States is here and we're here to stay," Kirby said.