China has come under mounting pressure over its land reclamation in the South China Sea, with both the United States and Japan criticising it for militarising the disputed waters.
US Secretary of State John Kerry raised the issue during a meeting with China's Foreign Minister Wang Yi on the sidelines of a regional diplomatic gathering in Malaysia that has been dominated by tensions over the Chinese moves.
"Secretary Kerry reiterated his concern about rising tensions over disputed claims in the South China Sea and China's large-scale reclamation, construction and militarisation of features there," a senior State Department official told reporters.
"He encouraged China, along with the other claimants, to halt problematic actions in order to create space for diplomacy."
China has sparked alarm by expanding tiny reefs in the disputed sea and constructing military posts on some of them to try to shore up its territorial claims.
The United States and Southeast Asian nations have called for a halt to such activities.
China has so far refused but on Wednesday (local time) Wang said land reclamation had "already stopped".
"China has already stopped. You look, who is building? Take a plane and look for yourself," he said to reporters.
A Southeast Asian diplomatic source, however, said Wang told his counterparts in the region at a high-level security forum that Beijing would press on with plans for construction on the newly created islands.
Southeast Asian foreign ministers warned Tuesday after they met in Kuala Lumpur that China's moves were raising regional tensions, with the Philippines slamming Beijing's "unilateral and aggressive activities".
State Minister Minoru Kiuchi, Japan's envoy to the talks, told delegates to the forum on Wednesday he had "deep concern over... large-scale land reclamation, the construction of outposts and their use for military purposes", according to a Japanese government statement.
Tokyo is locked in a confrontation of its own with Beijing over disputed islands in the East China Sea.
The annual gathering is hosted by the 10-member Association of Southeast Asian Nations (ASEAN), and includes the US, China, Japan, Russia and other countries.