A day earlier, on Monday, US Defense Secretary Ash Carter and his Singapore counterpart Ng Eng Hen signed an enhanced defense cooperation agreement, which includes the deployment of US Navy P-8 Poseidon surveillance aircraft to Singapore.
Foreign Ministry spokeswoman Hua Chunying told reporters at a Tuesday briefing that a stronger US military presence does "not conform to the common and long-term interests among the regional countries."
"So we hope the relevant side does more to enhance mutual trust among regional countries, and thus benefit the regional peace and development."
China claims most of the South China Sea, but there are overlapping claims from Singapore, Malaysia, Taiwan and the Philippines, among others. Beijing has constructed artificial islands in the disputed waters, alarming regional states and drawing criticism from Washington.
Prior to the agreement with Singapore, the United States was already launching military surveillance missions from Japanese and Philippine airfields, while continuing military patrols in the disputed waters.
Similarly, Singapore has long provided logistical support for US military ships and aircraft. Now, the new agreement paves the way for Washington to increase its surveillance in the region.
On Monday, the same day the agreement was signed, Washington deployed to Singapore a Poseidon surveillance aircraft. The deployment will last until December 14.
