The Pentagon is set to sell 100 Boeing-made Harpoon Coastal Defense Systems to Taiwan in a deal that has a potential value of up to $2.37 billion.
The move comes days after the State Department approved the potential sale of three other weapons systems to Taiwan, including sensors, missiles and artillery that could have a total value of $1.8 billion.
Monday's formal notifications to Congress by the State Department covered the proposed sale of up to 100 Harpoon Coastal Defense Systems (HCDS), which includes 400 RGM-84L-4 Harpoon Block II Surface Launched Missiles to serve as coastal defense cruise missiles.
The State Department sent notifications to Capitol Hill for the first tranche of arms sales which included truck-based rocket launchers made by Lockheed, Standoff Land Attack Missile Expanded Response (SLAM-ER) missiles and related equipment made by Boeing Co and external sensor pods for F-16 jets.
The deal involves 400 anti-ship cruise missiles, along with road-mobile launchers.
Although the Harpoon missile is an older technology, however, the fact that Taiwan is buying 100 of them will help in its defence.
According to the Center for Strategic and International Studies, Taiwan already has road-mobile supersonic missile, Hsiung Feng III which has a range of nearly 250 miles.
The two missile systems - Harpoon and Hsiung Feng III - would act as a deterrent against China military muscle, at least in the short run if hostilities break out between the two countries.
Lockheed Martin's sales strictly regulated by US government
The United States, like most countries, has no official diplomatic ties with Taiwan, but Washington is bound by law to provide the island with the means to defend itself.
The Trump administration has ramped up support for Taiwan through arms sales and visits by senior US officials, adding to tensions in relations between Beijing and Washington, already strained by disagreements over the South China Sea, Hong Kong, human rights and trade.
China has imposed sanctions on Lockheed Martin and other US companies in the past for selling weapons to Taiwan, however, Lockheed Martin said that all of its international military sales are strictly regulated by the US government.
Harpoon Block II surface-launched missiles
The 100 Harpoon Coastal Defense Systems (HCDS) includes 400 RGM-84L-4 Harpoon Block II surface-launched missiles with a range of around 78 miles (125 kilometers).
The missiles, manufactured by Boeing, can be positioned on fixed platforms or mounted on trucks.
Beijing said Tuesday it "firmly opposed" such moves, urging the US to "call off the relevant arms sales plan to Taiwan, so as not to cause further damage to China-US relations and peace and stability across the Taiwan Strait".
Simulated attacks on Taiwan-like territories and US bases in Guam
Chinese fighter jets and bombers have entered Taiwan's air defense zone with unprecedented frequency in recent months, while propaganda films have shown simulated attacks on Taiwan-like territories and US bases in Guam.
Foreign ministry spokesman Wang Wenbin said China would "take proper and necessary measures to firmly safeguard its national sovereignty and security interests."
135 air-to-ground missiles
The State Department said last week it had approved the sale of 135 air-to-ground missiles, in a move welcomed by Taiwan.
Also approved was the sale of six MS-110 air reconnaissance pods and 11 M142 mobile light rocket launchers, taking the value of the three arms packages to $1.8 billion.
A statement from the US State Department last week said the SLAM-ER missiles would help Taiwan "meet current and future threats".
The missiles provide "all-weather, day and night, precision attack capabilities against both moving and stationary targets" on the ground or ocean, the statement added.
US giants Lockheed and Boeing at the forefront
Earlier this month a top White House official urged Taiwan to build its military capabilities to protect against a possible invasion by China.
Beijing, in turn, has accused Washington of violating agreements signed in the 1970s establishing diplomatic relations between the two governments.
US giants Lockheed and Boeing were involved in a recent sale of $1 billion worth of missiles to Taiwan, alongside Raytheon.
The SLAM-ER missiles will help Taiwan "meet current and future threats as it provides all-weather, day and night, precision attack capabilities against both moving and stationary targets" on the ground or ocean surface, a statement said.
Constant threat of invasion by authoritarian China
Taiwan's defense ministry said the weapons would help it "build credible combat capabilities and strengthen the development of asymmetric warfare".
The sales announced Wednesday did not include the MQ9 Reaper combat drones, which Taiwan has also reportedly requested.
Democratic and self-ruled Taiwan lives under constant threat of invasion by authoritarian China, whose leaders view the island as part of their territory.
China's military defense spending dwarves Taipei's and while the US does sell Taiwan weapons, it is not bound by a defense treaty as it is with Japan, South Korea and the Philippines.
One China policy and Taiwan
Beijing has ramped up diplomatic and military pressure on Taiwan since the 2016 election of President Tsai Ing-wen, who views the island as a de facto sovereign nation and not part of "one China".
The last year has seen a dramatic increase in incursions by Chinese fighter jets and bombers into Taiwan's defense zone while state media has ramped up saber-rattling.
Last week, Beijing released footage of a military exercise simulating an invasion of a Taiwan-like territory featuring missile strikes and amphibious landings.