The United States army plans to store disaster relief equipment in Vietnam and Cambodia, a top American general has revealed.
General Dennis Via, who heads the US Army Materiel Command, told reporters at an Alabama symposium recently that the stockpiling of such equipment in these two countries is part of a broader strategy to pre-position supplies across the world for rapid deployment.
Unlike its pre-positioned supplies in Europe, which include tanks, those placed in this region will generally be "light" equipment geared towards humanitarian assistance, he was quoted as saying in online magazine Breaking Defense.
For example, he said, they were looking at placing a combat support hospital in Cambodia.
Thailand, a US treaty ally, was not mentioned as part of the arrangement.
Cambodia and Vietnam, which are both deepening their engagement with the US, are treading carefully to avoid rattling China, say analysts. China's shadow looms large in the region through its tourists, aid, investments and increasingly assertive claims over the South China Sea.
Vietnam's growing engagement with the US is in part spurred by recent Chinese incursions into what it considers its territory. Both China and Vietnam lay claim to the Paracel and Spratly islands.
"Vietnam is in a tough spot," said Ms Phuong Nguyen, an associate fellow at the US-based Centre for Strategic and International Studies. "More and more of its leaders recognise the importance of engaging more fully with the US, but the question is how to go about it in ways that are least likely to alarm or annoy China, its next-door neighbour and the main source of security threats surrounding Vietnam."
The two communist neighbours regularly cross swords, but also attempt to smooth ties, including through the recent reciprocal visits by envoys representing Vietnamese Communist Party chief Nguyen Phu Trong and his Chinese counterpart Xi Jinping.
Yet US-Vietnam ties are steadily growing. Last year, as the US lifted its embargo on sales of lethal maritime equipment to Vietnam, it also pledged US$20.5 million (S$28 million) - subject to appropriation - to support development of Vietnam's maritime capabilities. In August last year, a US navy hospital ship arrived at the central Vietnamese port of Danang for a disaster preparedness mission.
Meanwhile, US President Barack Obama is due to visit Vietnam in May.
There are some constraints on bilateral security engagements. Ships from the US navy are currently limited to one port call at Vietnamese facilities for a maximum of three ships every year.
But exceptions could be made for vessels on humanitarian missions, said Ms Nguyen, who added that both governments have discussed the possibility of turning Danang port into a regional hub for coordinating and storing supplies for humanitarian assistance and disaster relief.
The picture is rather different in Cambodia, say analysts. The kingdom, which has no direct interest in the South China Sea, is a major recipient of Chinese investment, development assistance as well as military aid.
By hosting US aid stockpiles, "Cambodia is hedging its bet - dating China, but not exclusive," said Cambodian specialist Sophal Ear, an associate professor of diplomacy and world affairs at California's Occidental College.
But Cambodia and the US are unlikely to have the kind of military rapprochement that Vietnam has seen with the Americans, he added.