A bipartisan trio of senators is urging the Trump administration to take tougher action to counter Chinese militarization in the South China Sea, voicing "grave concerns" over Beijing's regional encroachment.
Sens. Marco Rubio, Cory Gardner, and Ed Markey stated in a letter sent last week to the secretaries of state and defense that the administration's response to China's illegal maritime claims has been inadequate and is increasing the risk of conflict.
"We believe there is strong bipartisan congressional support for taking significant actions in response to the Chinese government's continuing militarization of the South China Sea," the senators said in the May 24 letter.
The letter was sent to Defense Secretary Jim Mattis and Secretary of State Mike Pompeo three days before the Navy sent two warships to the South China Sea on Sunday in a show of force.
U.S. officials said the warships, the USS Higgins, a guided-missile destroyer, and the USS Antietam, a guided-missile cruiser, sailed within 12 nautical miles of the Paracel Islands—an area of the northern part of the sea that China is claiming as its territory. Vietnam also claims the islands as its territory.
A Pentagon spokesman declined to comment directly on the latest freedom of navigation operation by the two warships.
China's military, however, called the warship passage a serious infringement of Chinese sovereignty carried out without Beijing's permission.
Defense Ministry spokesman Wu Qian said in a statement May 27 that Chinese warships warned off the American warships.
"The U.S. provocative action by sending once again warships into China's territorial waters surrounding the Xisha Islands violated Chinese law and relevant international law, seriously infringed sovereignty of China," Wu said, using China's name for the Paracels.
"The Chinese side is firmly opposed to such provocative and arbitrary actions by the U.S. side, which undermined strategic mutual trust between the two militaries and damaged peace, security, and good order in relevant waters," he added.
Wu said China's military would bolster naval and air combat readiness, and raise its military defense levels as a result.
The three senators stated in their letter that China's militarization of the South China Sea islands includes deployment of weapons on artificially-fortified islets and reefs in the Spratlys, including Fiery Cross Reef, Subi Reef, and Mischief Reef. The weapons activity is increasing China's ability to project power into the Pacific Ocean, they stated.
China has reclaimed some 3,200 acres of small islands since 2013 and in recent years built military bases that have included airstrips, hangars, harbors, anti-aircraft batteries, radars, and structures for housing surface-to-air missiles.
In recent weeks, Chinese forces also landed several nuclear-capable H-6K bombers on one South China Sea airfield, and deployed anti-ship cruise missiles and surface-to-air missile systems, on three separate man-made islands in the Spratlys.
The buildup violated Chinese President Xi Jinping's promise during a summit in September 2015 with then-President Barack Obama that China would not "pursue militarization" of the islands, the senators noted.
The senators, in their letter, repeated recent comments by the incoming Pacific Command commander, Adm. Philip Davidson, who testified in April that China is close to taking control of the strategic waterway.
The South China Sea is used to transport an estimated $5 trillion annually in global trade.
"The only thing lacking [by the Chinese military's expansion activities the South China Sea] are the deployed forces," Davidson said. "Once occupied, China will be able to extend its influence thousands of miles to the south and project power deep into Oceania."
Rubio (R., Fla.), Gardner (R., Colo.), and Markey (D., Mass.) also said missiles being deployed on the islands are not defensive and will increase China's offensive firepower. The missiles provide China with new coercive power in regional disputes, including with U.S. ally Philippines, Vietnam, and Indonesia.
Recent Senate actions indicate growing congressional support for stronger initiatives.
In April, a bipartisan group of senators sponsored legislation calling for a new policy framework in the Indo-Pacific region to promote a free and open region and adherence to a rules-based international order.
A section of that bill calls for regular warship operations and military flights over the sea, and greater joint maritime training and freedom of navigation operations with regional states.
The bill also would fund weapons transfers and greater defense cooperation in the region "to resist coercion and to deter and defend against security threats," the senators said.
Earlier in March, another group of senators, led by Rubio and Sen. Ben Cardin (D., Md.) introduced legislation that would impose sanctions on Chinese officials and organizations engaged in illegitimate actions in both the South China Sea and East China Sea, where China is pressing Japan over its claims to the Senkaku islands.
"The Chinese government's latest aggressive actions clearly demonstrate that continued brow-beating of Beijing via diplomatic demarches is not enough," the three senators stated.
The senators said the administration needs to do more to force China into accepting the 2016 ruling of the international tribunal in The Hague that ruled China violated international law by building up the artificial islands.
Additionally, Rubio, Gardner, and Markey want the administration to work more with Congress to provide robust U.S. military support to regional states concerned about Chinese aggression.
Other measures sought include reaching a trilateral agreement between the Pentagon and Japan and Australia to coordinate maritime security assistance and pool resources.
"We were glad to see the Department of Defense recently retract U.S. invitations for the People's Liberation Army Navy to participate in the upcoming Ring of the Pacific (RIMPAC) naval exercise," the senators said.
In addition, the senators want the Pentagon to provide an assessment of the threat posed by China's new regional weapons to freedom of navigation operations in the South China Sea.
A third proposal is the creation of a Joint Maritime Task Force-Pacific that would provide "persistent deployment of surface ships from a group of allies and partners in the broader Indo-Pacific region who are committed to protecting a free and open South China Sea maritime environment," the lawmakers said.
Reuters reported that satellite photos taken May 12 revealed China has deployed mobile surface-to-air missiles or anti-ship cruise missiles on Woody Island in the Paracels.
Marine Corps Lt. Col. Christopher B. Logan said in response to reports of the warship operation: "U.S. forces operate in the Asia-Pacific region on a daily basis, including in the South China Sea. All operations are conducted in accordance with international law and demonstrate that the United States will fly, sail, and operate wherever international law allows."
"We are continuing regular FONOPS, as we have routinely done in the past and will continue to do in the future," he said, adding that summaries of the operations would not be released until an annual report is made public.
China's claims to islands in the sea have been challenged by Philippines, Vietnam, Brunei, Malaysia, and Taiwan.