Chinese officials reacted angrily Saturday to Defense Secretary Chuck Hagel's suggestions that China was using "intimidation, coercion" and the "threat of force" to assert its claims in the South China Sea.
Hagel's remarks charging China "has undertaken destabilizing, unilateral actions asserting its claims" prompted an immediate rebuke from Beijing.
The Defense secretary's comments, made at a conference of senior international military officials in Singapore, referred to China's oil drilling off the coast of Vietnam and a land reclamation project on a disputed reef claimed by the Philippines.
China's representatives at the conference responded by accusing the United States of provoking tensions in the region.
"We are in the 21st century. We should not keep on resorting to the 20th century mentality that is about war and conflict," said Fu Ying, head of the China delegation and a former diplomat, according to China's official Xinhua news service.
The Chinese were also furious over remarks made Friday by Japanese Prime Minister Shinzo Abe calling for Japan to take a "greater and more proactive role" in regional security. Abe announced that Japan was providing the Philippine coast guard with 10 new vessels and intends to give boats to Vietnam as well.
Alluding to World War II, China accused Abe of trying to remilitarize Japan.
"This should be all the more worrying when it becomes the banner of a country that invaded and occupied a large part of Asia and still is reluctant to come to terms with its militarist past," Xinhua wrote in a commentary Saturday.
The back-and-forth comes in the midst of a tense period in the South China Sea, where Beijing's territorial claims overlap with those of its neighbors. More than 100 Chinese and Vietnamese ships have been circling each other around a giant Chinese-owned oil rig 150 miles off the coast of Vietnam.
Last week a Vietnamese fishing boat was rammed and sunk by a Chinese vessel in the area.
That followed days of rioting in Vietnam in which Chinese-owned factories were torched and looted.
The Philippines, meanwhile, has accused China of moving earth and construction materials to expand what is known as Johnson South Reef, perhaps to build an airstrip that would bolster its presence.