The United States have said it is "reassessing" China's participation in a large naval drill in the Pacific this year, amid tensions with Beijing over maritime claims.
China took part in RIMPAC -- the largest international naval exercises in the Pacific involving some 20 countries every two years under US leadership -- for the first time in 2014.
But soon after China's initial participation, aimed at reducing distrust, renewed incidents caused tensions to flare up anew.
China's land reclamation and military buildup in the South China Sea have drawn international condemnation, including from the United States.
The Chinese "have an invitation for RIMPAC and we will continue to review that," Defense Secretary Ashton Carter told the House Armed Services Committee.
"Our strategy in the Asia Pacific is not to exclude anyone, but to keep the security architecture going there, in which everyone participates," he testified at a hearing.
"China is, however, self-isolating... That's why all these partners are coming to us."
"We are constantly reassessing" the opportunity to have China participate in the exercise, Carter added.
US Pacific Command chief Admiral Harry Harris has warned lawmakers that Beijing was "clearly militarizing" the South China Sea.
Washington recently struck an accord with the Philippines, making it possible for US forces to rotate through five bases there -- including those close to the South China Sea.
China claims virtually all the South China Sea, despite conflicting partial claims by Brunei, Malaysia, Vietnam, Taiwan and the Philippines.
It has been asserting its claim by occupying more reefs and outcrops in these waters, and building artificial islands, including airstrips on some of them.
This year, RIMPAC is due to take place in June and July. RIMPAC 2014 involved 23 counties, some 50 ships, six submarines and more than 25,000 troops.
