China's cutting of some of its few communication links with the US military raises the risk of an accidental escalation of tension over Taiwan at a critical moment, according to security analysts, diplomats and US officials.
China called off planned formal talks involving theatre-level commands, defence policy co-ordination and military maritime consultations on Friday as part of its retaliation against US House Speaker Nancy Pelosi's visit to Taiwan this week.
In an editorial on Saturday, the Communist Party's People's Daily newspaper described the response, along with sanctions against Pelosi and her family, as "effective measures that fully demonstrates that China is fully determined and capable of safeguarding national unity and safeguarding ... sovereignty and territorial integrity".
Christopher Twomey, a security scholar at the US Naval Postgraduate School in California, told Reuters the severing of the communication links was worrying, coming at what he believed was the beginning of a new Taiwan crisis.
China fired ballistic missiles over Taipei as part of four days of unprecedented military drills around the island it claims as its own - exercises due to end at noon on Sunday.
"This increased density of forces, in the context of an intensifying crisis, raises the prospect for inadvertent escalation that neither side wants," Twomey said, speaking in a private capacity.
"That is precisely the time you would want to have more opportunities to talk to the other side ... Losing those channels greatly reduces the ability of the two sides to de-conflict military forces as various exercises and operations continue."
As Chinese warships, fighter jets and drones manoeuvre around Taiwan, at least four powerful US vessels, including the aircraft carrier USS Ronald Reagan, the amphibious assault ship USS Tripoli and the guided missile cruiser USS Antietam are east of Taiwan, Reuters has confirmed.
Not taking calls
Bonnie Glaser, a Washington-based security analyst with the German Marshall Fund of the United States, said, more broadly, prospects were "extremely low for holding talks on risk reduction measures or stability".
Over time, she said she expected the specific talks called off this week would resume but "right now, China has to signal toughness and resolve".
A US official, speaking on condition of anonymity, said Chinese officials had not responded to calls from senior Pentagon officials this week but that was seen as China showing displeasure over Pelosi's trip rather than the severing of the channel between senior defence officials, including US Defense Secretary Lloyd Austin.
Austin pushed for improved communication between the rival forces when met Chinese Defence Minister General Wei Fenghe on the sidelines of Shangri-la Dialogue security meeting in Singapore in June.
Both Asian and Western diplomats said US military chiefs had been pushing for more frequent theatre-level command talks for some time, given China's growing deployments across Asia, where the US navy has traditionally been the dominant power.
The Pentagon said on Friday that China was overreacting and the United States was still open to building crisis communication mechanisms.
"Part of this overreaction has been strictly limiting its defence engagements when any responsible state would recognise that we need them now the most," acting Pentagon spokesman Todd Breasseale said.