Kuala Lumpur: US Secretary of State John Kerry voiced concern to China on Wednesday over its land reclamation in the South China Sea and the “militarisation” of its disputed waters.

Kerry raised the issues during a meeting with Chinese Foreign Minister Wang Yi on the sidelines of a regional diplomatic gathering in Malaysia that has been dominated by tensions over China’s moves to shore up its territorial claims.

“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 in the region by expanding tiny reefs in the flashpoint sea and constructing military posts on them.

The US and Southeast Asian countries have called for a halt to such activities, but China has refused.

A day earlier, Southeast Asian foreign ministers warned after they met in Kuala Lumpur that China’s moves were raising regional tensions, with the Philippines slamming Beijing’s “unilateral and aggressive activities”.

The annual gathering is hosted by the 10-member Association of Southeast Asian Nations (ASEAN), and includes countries from across Asia, the US, Russia and elsewhere. It continues until Thursday.

Beijing claims control over nearly the entire South China Sea, a key shipping route thought to hold rich oil and gas reserves.

Vietnam, the Philippines, Malaysia and Brunei — all ASEAN members — also have various claims, as does Taiwan, many of which overlap.

China’s neighbours have increasingly chafed at what is seen as mounting violations by Beijing of a regional pledge not to take actions that could stoke conflict.

Before their meeting, Kerry had said he and Wang were also to discuss a range of bilateral issues including plans for a September US visit by Chinese President Xi Jinping and China’s “great cooperation” on the recent Iran nuclear deal.

A US diplomat also said Kerry would meet with his Russian counterpart Sergei Lavrov later on Wednesday to “discuss a range of issues of mutual concern”.

They last met in Doha on Monday alongside Saudi Foreign Minister Adel Al Jubeir, where the ongoing civil war in Syria topped the agenda.

After that meeting, Lavrov hit out at an announcement by Washington that it was willing to take extra measures to defend US-allied fighters in Syria, describing the plan as “counterproductive”.

Kerry, in a meeting on Wednesday with ASEAN foreign ministers, said Washington shared their desire “to preserve peace and stability in the South China Sea”.

He stressed the need to maintain the security of sea lanes and fishing grounds and to settled disputes peacefully.

Beijing has insisted it will not discuss the South China Sea during formal meetings at the forum, saying disagreements must be handled on a bilateral basis between rival claimants.

Diplomats and analysts say this stance is aimed at preventing ASEAN from presenting a more united front.

A Washington-based think tank said this week Beijing could be preparing to build a second airstrip on an artificial island.

China is already building a 3,000-metre runway on Fiery Cross reef, which could ultimately be used for combat operations, according to the Centre for Strategic and International Studies.