The United States this weekend advised US commercial airlines to notify Chinese authorities of flight plans over the East China Sea, although a US official said that did not mean Washington accepted China's new rules.

The directive came as tensions escalated over disputed islands in the East China Sea. China scrambled jets on Friday in response to two US spy planes and 10 ­Japanese aircraft entering its new air defence zone.

China last week announced that foreign aircraft passing through the new air defence zone should identify themselves to its authorities.

"The US government ­generally expects that US ­carriers operating ­internationally will ­operate consistent with Notams (Notices to Airmen) issued by foreign countries," the State Department said in a statement. "Our expectation of operations by US ­carriers consistent with Notams does not indicate US ­government acceptance of China's requirements."

On Wednesday, State ­Department spokeswoman Jen Psaki said US carriers were being advised to take steps to operate safely over the East China Sea, but she did not know whether the new rules would affect commercial airlines.

A US administration ­official said on Friday that China's action appeared to be an attempt "to unilaterally change the status quo in the East China Sea and thus will raise regional tensions and increase the risk of miscalculation, confrontation and accidents." The official added: "We urge the Chinese to exercise caution and restraint, and we are consulting with Japan and other affected parties, throughout the region."

Beijing's new rules mean aircraft have to report flight plans to China, maintain radio contact, reply promptly to ­identification inquiries and display clear markings of their nationality and registration.