nhk world's charmaine deogracias reports. >> reporter: some u.s.roops and military personnel are taking part in 12 days of war games. the exercises kicked off on monday and are designed to strengthen ties and improve joint military capabilities to protect philippine borders. the drills include landing practice on the western island in the south china sea. in addition it the bilateral naval exercises, the capital manila will host an earthquake simulation with six southern nations, including japan, for the first time. >> this will undoubtedly constitute -- or contribute to the nations in the region having increased level of trust and cooperation to ensure regional stability. >> we continue to work together for a secure and stable asia-pacific region. >> reporter: this year's exercises have been marked by political tension. following a naval standoff between the philippines and china. on tuesday last week, a philippine navy ship and chinese surveillance vessels faced each arth the disputed scarborough shoal off the philippine island of luzon. diplomat

nhk world's charmaine deogracias reports. >> reporter: some 4,500 u.s. troops and 2,300 philippine personnel are taking part in 12 days of war games. the exercises kicked off monday and designed to strengthen ties and improve joint military capabilities to protect philippine borders. the drills include landing practice on the western island of palau in the south china sea. in addition to the bilateral naval exercises, the capital manila will host an earthquake simulation with six other nations, including japan, for the first time. >> this will undoubtedly constitute or contribute to the nations in the region having increased level of trust and cooperation to ensure regional stability. >> we continue to work together for a secure and stable asia-pacific region. >> reporter: this year's exercises have been marked by political tension following a naval standoff between the philippines and china. on tuesday last week, a philippine navy ship and chinese surveillance vessels faced each other at the disputed scarborough shoal off the philippine island of luzon.