China said the United States' deployment of spy planes in Singapore for surveillance in the South China Sea was out of step with the region's interests, but it stopped short of directly criticising the Republic.

Observers say China gave a restrained response to preserve its strong ties with Singapore and also because it is likely to have been informed in advance by Singapore.

At the Chinese foreign ministry's regular briefing in Beijing yesterday, spokesman Hua Chunying said China believes most of its neighbours, including Singapore, wish to see an East Asia that is peaceful, stable and prosperous.

She called for deep reflection on whether actions by countries like the US in beefing up military deployment and militarising the region are in sync with the wish of other countries, "especially in view of the peaceful and stable situation in the South China Sea".

"I believe the US actions in beefing up its military deployment and militarising the region do not meet the joint long-term interests of the countries in this region," she added.

"We hope relevant parties would do more to increase trust between countries and maintain regional peace and stability."

Beijing has also been criticised for militarising the region through its land reclamation and construction of military facilities in the South China Sea that faces overlapping claims from China, Vietnam, the Philippines, Malaysia, Brunei and Taiwan.

Sino-Asean expert Xu Liping of the Chinese Academy of Social Sciences said China would have made direct criticism if the P-8 deployment had been in the Philippines or Vietnam.

"China's response showed it understands that Singapore still depends heavily on the US for its security needs, which cannot be changed in the near future," he said.

"China also knows criticising Singapore would not stop the deployment and might create more problems by hurting bilateral ties."

Kor Kian Beng