According to China's defense minister, a war with the US would be an "unbearable disaster" for the entire world and that his nation preferred to avoid war through dialogue.
General Li Shangfu stated at a security summit that "some countries" were escalating an arms race.
However, he asserted that the world was big enough for both China and the US and that the two superpowers should look for areas of agreement.
In the Taiwan Strait, a Chinese destroyer had earlier engaged in "unsafe" maneuvers close to a US warship.
In response to US sanctions imposed on Gen Li in 2018 over weapons purchases from Russia, Beijing has rejected a US request for direct military talks.
Gen Li said at the Shangri-La Dialogue, the only annual security gathering for the Asia-Pacific, that "China and the US have different systems and are different in many other ways. ".
According to the Reuters new agency, he warned delegates that "a Cold War mentality is now resurgent, greatly increasing security risks.".
Bullying and hegemony should give way to mutual respect, continued Gen Li.
Since becoming the defense minister in March, Gen Li had not previously given a significant speech abroad.
China's claim to Taiwan and territorial disputes in the South China Sea are just two of the issues that have soured relations between Washington and Beijing in recent years.
The Taiwan Strait was being crossed by Canadian and American ships on Saturday when the US navy reported that a Chinese destroyer was sailing "in an unsafe manner" close to an American warship.
China has criticized both nations for "intentionally provoking risk.". According to the US and Canada, they were sailing within the bounds of international law.
A video of a Chinese jet flying dangerously close to a US surveillance plane in the South China Sea was also made public by the Pentagon last month. They described it as an "unnecessarily aggressive manoeuvre.".
US Defence Secretary Lloyd Austin chastised China for refusing to hold military talks at the Singapore summit.
Gen Austin and Gen Li shook hands and conversed briefly but informally during the event's opening dinner on Friday, according to the AFP news agency.
A delegate from China told AFP that the lifting of US sanctions against Gen Li was a requirement for negotiations.
A senior US state department official has arrived in Beijing for a week of extensive negotiations despite the diplomatic spat.
At the summit, a gathering of spy chiefs was attended by senior intelligence officials, according to Reuters.
