China has warned it would take new measures in response to a planned U.S. arms sale to Taiwan, a self-ruling island claimed by Beijing, which also called out Washington partners India and Japan over territorial disputes across Asia.

Chinese Foreign Ministry spokesperson Zhao Lijian decried the sale of three advanced weapons systems to Taiwan. He called it a violation of the longstanding agreements by which Washington has foregone direct ties with Taipei in favour of Beijing.

"The United States has seriously violated the one-China principle, and the provisions of the three China-U.S. joint communiqués, especially the August 17 communique," Zhao said, "by selling arms to Taiwan, seriously interfered in China's internal affairs and seriously harmed China's sovereignty and security interests."

"China firmly opposes this," he warned, calling on the U.S. side "to fully recognize the very damaging nature of its arms sales to Taiwan, abide by the one-China principle and the provisions of the three China-U.S. joint communiqués, immediately cancel all arms sales plans to Taiwan, and stop arms sales to Taiwan and military ties between the United States and Taiwan."

Without specifying, Zhao said there would otherwise be consequences to Washington's decision.

"China will make a legitimate and necessary reaction in the light of the development of the situation," Zhao said.

News of the approval of the three weapons systems reportedly came in the way of an informal congressional notification passed on to House Foreign Relations Committee and Senate Foreign Affairs Committee leadership, as several outlets such as Reuters, The Hill and Defence News reported.

A House Foreign Affairs Committee aide, a congressional aide and a source familiar with the notifications confirmed to Newsweek that Capitol Hill received information notification of the three sales over the weekend.

The committee is "inclined to support" the sales, "as well as any additional sales that will support strengthening Taiwan's defence capacity, including the ability to counter threats across the Taiwan strait," the House Foreign Affairs Committee aide told Newsweek.

The equipment involved was said to include a Lockheed Martin-developed multiple launch weapon called the M142 High Mobility Artillery Rocket System, Boeing-made long-range air-to-surface cruise missiles called SLAM-ER and external sensor pods for F-16 fighter jets.

The news broke shortly after Newsweek reported on Taiwan's drive for more domestically-produced and U.S.-made weapons to deter a potential Chinese attack.

"Taiwan will continue to increase investments in its defence commensurate with the security challenges it faces," Andrew Yang, spokesperson of the Taipei Economic and Cultural Office in New York, told Newsweek at the time. "Taiwan will also seek security cooperation with the United States to build its defence systems that are cost-effective but lethal enough to make any invasions painful."

Taiwanese President Tsai Ing-wen also vowed to build and buy more powerful defences during National Day celebrations over the weekend. She promised to defend the island, while calling for dialogue with the mainland, which continued to raise the temperature across the disputed strait by sending Y-8 anti-submarine warfare aircraft into the air defence identification zone claimed by Taiwan.

Chinese forces have also conducted military exercises along the coast and in the waters dividing the People's Republic from the island officially calling itself the Republic of China.

Since losing a civil war to Chinese Communist Party in 1949, Taiwan's diplomatic relations have shrunken to just 14 countries, a fall that became precipitous as Beijing opened economically to the West and gained China's United Nations seat in the 1970s. But the U.S. still remains engaged as a security partner with Taiwan, and these unofficial ties have been expanded under President Donald Trump's administration. But neither he nor his officials have yet to break the strategic ambiguity of whether or not the U.S. would come to Taiwan's aid in the event of a Chinese attempt to reunify by force.

Confronted Friday with questions by radio host Hugh Hewett about U.S. commitments to Taiwan, Secretary of State Mike Pompeo vowed to live up to agreements such as "weapons sales to Taiwan" and reiterated the "willingness of our military to ensure the freedom of navigation in and around Taiwan," even if they drew anger from China.

"These are the obligations that the United States should undertake and is undertaking," Pompeo said. "We recognize that this is a point of conflict with the Chinese Communist Party. We don't want that. We want peace. But we are going to make sure that we live up to all of the obligations we have to Taiwan."

China is also involved in other disputes over territory with countries growing closer to the U.S. as well.

Bilateral efforts continue to seek an end to a bloody standoff between Chinese and Indian forces at a Himalayan crossing point between China-administered Aksai Chin and India-administered Ladakh. The two sides met Tuesday at the India-controlled village of Chushul for their seventh round of military talks.

A joint statement sent to Newsweek by an Indian defence official described "a sincere, in-depth and constructive exchange of views on disengagement along the Line of Actual Control in the Western Sector of India-China border areas."

"They were of the view that these discussions were positive, constructive and had enhanced understanding of each other's positions," the statement said. "Both sides agreed to maintain dialogue and communication through military and diplomatic channels, and arrive at a mutually acceptable solution for disengagement as early as possible."

The two armed forces also agreed "to earnestly implement the important understandings reached by the leaders of the two countries, not to turn differences into disputes, and jointly safeguard peace and tranquillity in the border areas."

But a harsher tone came from Beijing, where Zhao denounced New Delhi's decision to build a series of bridges providing all-weather access to the disputed border region with China. He called it a potential violation of their most recent consensus and demanded India change course.

"For a while, the Indian side has been stepping up infrastructure building and military deployment along the border with China. This is the root cause of tensions," Zhao said. "We urge the Indian side to earnestly implement the consensus reached by the two sides, refrain from taking actions that will complicate the situation, and take concrete measures to safeguard peace and tranquillity along the border."

Beijing and New Delhi once went to war over their ill-defined border in the 1960s and have clashed periodically since. The latest skirmishes, which turned deadly in June, have proven to be the worse in decades, and come as the U.S. seeks to court India in efforts to contain China's regional posture.

Japan is also involved in these efforts, as they are locked in a territorial contest of their own with China, this time at sea.

Chinese fishing vessels have regularly sailed near the East China Sea's Pinnacle Islands. Japan administers these islands, which they call Senkaku, but the Chinese government also claims them under their own name, Diaoyu. The latest activity has persisted for a record-breaking length of time and on Sunday involved an actual violation of the declared Japanese maritime border.

Back in Beijing, Zhao had an opposing view on this regional matter as well.

"Diaoyu Dao and its affiliated islands are China's inherent territory," Zhao told Tuesday's press briefing. "Patrolling and carrying out law enforcement activities in the relevant waters are also China's inherent right. The Japanese side should respect this."

East China Sea issues also came up in conversation Monday between Kishi and his counterpart from Australia, the fourth member of the Quadrilateral Security Dialogue that met last week in Tokyo. At the gathering, Pompeo said it was urgent that the U.S., Australia, India and Japan "collaborate to protect our people and partners from the CCP's exploitation, corruption, and coercion."

Beijing's embassy in Washington dismissed Pompeo's position in a reaction sent to Newsweek.

"China is committed to the path of peaceful development and firmly safeguards its sovereignty, security and development interests," the Chinese embassy spokesperson said at the time.

"At the same time, it is committed to resolving differences with other countries through dialogue and consultation," the spokesperson added. "This is what we say and also what we do. We do not accept reckless smearing and groundless accusations against China."