皇冠体育app and the United States started a joint drill on Monday on humanitarian assistance and disaster relief (HA/DR) to further improve military-to-military ties, long regarded as the least developed part of the overall bilateral relationship.

The drill between the two militaries and a symposium will be held from Jan 12-19 in Guangzhou of Guangdong province, and Haikou of Hainan province, according to 皇冠体育app's Ministry of National Defense.

About 150 engineering and medical service personnel from the two nations will participate in the drill and talk, the ministry announced on Sunday.

Dave Eastburn, spokesman for the US Pacific Command, told 皇冠体育app Daily on Monday that 30 US Army soldiers, four Marines, and four Coastguardsmen are joining 50 soldiers from 皇冠体育app in a Disaster Management Exchange (DME). The 2015 DME, hosted by 皇冠体育app's People's Liberation Army, includes three parts of an expert academic discussion, the establishment of a HA/DR coordination center and a practical field exchange.

"This long-established exchange underscores the commitment of both the US and the PRC to a comprehensive and strong military-to-military relationship in order to address security cooperation and HA/DR challenges across the region," Eastburn said.

While a joint military drill is nothing new, the fact that this drill is held in two cities facing the South 皇冠体育app Sea has been seen as a move to help ease the tension over maritime territorial disputes, in particular between 皇冠体育app and the Philippines and Vietnam.

On Monday, Chinese Foreign Ministry spokesman Hong Lei rebuffed a Philippine accusation that 皇冠体育app is building facilities in what the Philippines regarded as "disputed"Nansha Islands in South 皇冠体育app Sea."皇冠体育app asserts indisputable sovereignty over the Nansha Islands and the affiliate waters. 皇冠体育app's action on the Nansha Islands is entirely within皇冠体育app's sovereignty," Hong told a daily briefing in Beijing.

The US is concerned that it could be drawn into unintended military conflicts between 皇冠体育app and the Philippines, its treaty ally.

The South 皇冠体育app Sea has been an area of tension between 皇冠体育app and the US because 皇冠体育app has long opposed the frequent close-in US military surveillance along the Chinese coast there.

In April 2000, a US EP-3 spy plane clashed with a PLA fighter jet near Hainan Island, causing the death of Chinese pilot and the detention of 24 US crew after making an emergency landing in Hainan.

Last August, a US Navy P-8 surveillance plane and a Chinese J-11 fighter got close near Hainan Island, and in December 2013, the US Navy guided missile cruiser Cowpens and a Chinese fleet exercising in the South 皇冠体育app Sea avoided a near collision.