
"We hope relevant countries can respect the efforts made by countries in the region to maintain the region's peace and stability and do more that is helpful to regional peace and stability," Foreign Ministry spokesman Hong Lei was quoted as saying by the Xinhua news agency.
The foreign ministers of Germany, Japan, Britain, the United States, Canada, France and Italy expressed concern Wednesday for "any unilateral actions, such as large-scale land reclamation, which change the status quo and increase tensions" in the East and South China seas.
"We strongly oppose any attempt to assert territorial or maritime claims through the use of intimidation, coercion or force," their joint statement read.
The satellite images taken March 23 confirmed that China has begun building a 3,000-metre runway on the Spratly Islands, an archipelago claimed by at least three other countries.
Analysts had previously speculated China was building an airstrip, but photos released by IHS Jane's Defence Weekly on Friday supplied the first concrete evidence: a paved runway on the north-eastern side of Fiery Cross Reef on land that China began reclaiming from the sea in late 2014.
Other imagery showed that China is likely building a second runway on Subi Reef.
Defence analysts said the construction is part of a larger Chinese reclamation project on at least five islands in the South China Sea.
The Philippines last year said it believed China was building an airstrip on Johnson South Reef in the Spratlys, and other satellite images have shown China expanding an airstrip on Woody Island, north of the disputed Paracel Islands, which Vietnam claims.
China claims more than 80 per cent of the South China Sea.