US Defence Secretary Lloyd Austin said on Sunday he saw no imminent move on Taiwan by China, but Beijing was trying to establish a "new normal" with its military activities around the island.
A visit to Taiwan early in August by US House of Representatives Speaker Nancy Pelosi enraged China, which late launched military drills near the island. Those have continued, although on a much reduced scale.
"I don't see an imminent invasion," Mr Austin told CNN.
"What we do see is China moving to establish what we would call a new normal. Increased activity — we saw a number of centre line crossings of the Taiwan Strait by their aircraft.
"That number has increased over time. We've seen more activity with their surface vessels and waters in and around Taiwan."
The US and its allies have responded to the drills by continuing to sail through the region. A US Navy warship and a Canadian frigate made a routine transit through the Taiwan Strait on September 20.
The US will continue to work with its allies and partners "to ensure that we maintain a free and open Indo-Pacific," Mr Austintold CNN's Fareed Zakaria GPS recorded on Friday.
The narrow Taiwan Strait has been a frequent source of military tension since the defeated Republic of China government fled to Taiwan in 1949 after losing a civil war with the communists, who established the People's Republic of China.
The US is working to reopen channels of military communication with China, something that is critical to both countries, Mr Austin said.
China in August halted co-operation with the US in areas including dialogue between senior-level military commanders, in retaliation for Ms Pelosi's visit to Taiwan.
Mr Austin said he has communicated by phone and in person with his Chinese counterpart, Defence Minister Wei Fenghe, who agreed that open communications were important.
"We'll do everything we can to continue to signal that we want those channels open and I would hope that China will begin to lean forward a bit more and work with us," he said.
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