China's unprecedentedly strong countermeasure of canceling Sino-US military talks has demonstrated the nation's resolve to safeguard its core interest, which was seriously violated by United States House Speaker Nancy Pelosi's visit to Taiwan, observers said.

The risks of conflict or even confrontation between the world's top two militaries are getting high after the cancellations of key communication mechanisms, they said, stressing that the US, which has a hegemonic mentality, should be held fully responsible for the current situation.

Of the eight countermeasures the Foreign Ministry announced on Friday, the first three canceled vital China-US military dialogues, including the Theater Commanders Talk, the Defense Policy Coordination Talks and the Military Maritime Consultative Agreement meetings.

Zhou Bo, a senior fellow at Tsinghua University's Center for International Security and Strategy and a retired People's Liberation Army officer, said these measures are "unprecedentedly strong".

That the first three measures relate to exchanges between the two militaries "shows how determined China is in voicing its determination or indignation against Pelosi's visit," he said.

Zhou's opinion is shared by a PLA international relations researcher, who is familiar with the China-US military communications and asked to remain anonymous.

"Those countermeasures were quite strong and weighty," the researcher said, stressing that the talks that were canceled made a "major difference in learning from each other's views and managing risks".

"The canceled dialogues, especially the DPCT and MMCA, were very important for the two countries to know about their concerns and enhance the mutual trust," he said, adding that in the past, some actions or opinions of both sides could be adjusted through the key communication mechanisms.

The DPCT was established in 2005, and the MMCA in 1998. The most recent video meetings under the two mechanisms were held last year. In them, the two sides exchanged views on issues of common concern and discussed the maritime and air security situation and improvement measures, according to the Ministry of National Defense and Chinese embassy in the US.

Maintaining communications is important for China and the US, particularly amid the unprecedented tensions between two of the world's major powers, the researcher said.

"The less information-sharing and communications the two countries have, the more possible and faster it is that they could come into conflict and even confrontation," he said.

Compared with the other five countermeasures, related to suspending justice and climate cooperation, the cancellation of military talks highly likely also could mean that there is "no possibility to get them resumed" in the future, the anonymous source said, adding that there are few communication channels between the militaries of China and the US, which has been "strategically anxious" about China's rapid growth in recent years.

In addition to the canceled dialogues, the Chinese and the US militaries have set up several communication mechanisms in the past 25 years to actively strengthen strategic communication and manage risks and differences. These include the Defense Consultative Talks, established in 1997, the direct telephone line between China-US defense ministries, opened in 2008, and the joint staff dialogue mechanism, set up in 2017, according to defense white papers released by the State Council Information Office.

However, the last Defense Consultative Talks were held in 2014, after which no public information about them has been available.

Meng Xiangqing, a senior researcher at PLA National Defense University, told China Central Television on Saturday that the risks between the two militaries are getting higher, and the US should be held fully responsible for the current situation.

"For a long time, China and the US have both maintained communications in terms of regional security affairs," he said. "However, as is evident from what happened recently, the US didn't keep its commitment to the one-China principle, despite the China-US military communications, and even made things worse."

The atmosphere of bilateral military cooperation and the mutual trust has been damaged by the US military, Meng said, stressing that it has seriously undermined the political foundation of the ties between the two sides and violated the three China-US joint communiques by providing a so-called security guarantee for Pelosi's visit.

"As a consequence, we have no choice but to cancel these military talks as a countermeasure," Meng said, adding that the US must give up its hegemonic and Cold War mentality so that the bilateral ties can return to normal in the future.