China urged the United States on Thursday to stop its close surveillance by patrol aircraft near Chinese territory if it seriously wants to repair damaged bilateral ties.

Speaking at a news conference, Yang Yujun, spokesman for the Ministry of National Defense, denied a claim by the US State Department that Washington had told Beijing of the reconnaissance flights and that the missions are "open and transparent".

"There has been no notification in advance" every time the US sent aircraft to conduct close-in reconnaissance near Chinese territory, he said.

Frequent US reconnaissance of China made headlines again last week. A Chinese navy J-11 fighter jet took off to conduct routine identification and verification work on Aug 19 as US Navy P-3 and P-8 planes were conducting reconnaissance missions about 220 km from Hainan Island.

Chinese military observers said the US conducted about 500 such China reconnaissance operations every year.

"If an action is wrong, then whether it is transparent or not, or whether other nations were notified, does not make any difference to the error in the nature of such an action," Yang said.

Such actions "will lead to maritime or airspace accidents" and are not conducive to building mutual trust between the two militaries.

"If the United States does not want to affect bilateral ties, it must reduce and ultimately stop such reconnaissance," Yang said.

Zhang Junshe, deputy director of China's Naval Military Studies Research Institute, said the US spy flights pose a huge threat to security because the US planes often fly a route close to China's territorial waters, about 12 nautical miles from the coastline.

"This has seriously threatened China's national security and has led to accidents, Zhang said.

The incident on Aug 19 served as a reminder of the collision between a Chinese PLA navy J-8 fighter jet and a US Navy EP-3 spy plane off Hainan Island on April 1, 2001. Chinese pilot Wang Wei was killed and the EP-3 plane forced to land on Hainan Island.

Jen Psaki, spokeswoman for the US State Department, said on Monday, "Both State Department and Department of Defense officials expressed strong concern to the Chinese about the unsafe and unprofessional interception last week."

Yang denied the allegation and said Chinese pilots operate professionally and take safety into consideration.

"As a developing country, China values its aircraft and pilots' lives, when compared with some countries that have their military pilots fly close to others' doorsteps on a daily basis," Yang added.

Xinhua contributed to this story.