The joint military exercise "Cormorant Strike III", which started on September 10, is taking place in Sri Lanka's east, the army said.
In addition to about 2,000 local tri-service personnel, the 16-day combined military exercise is being attended by 40 foreign military personnel representing India, China, Pakistan, Bangladesh and Maldives. Eleven of the 40 foreign representatives are officers.
The exercise involves amphibious landing followed by operation on land under simulated combat action.
It underlines the importance of sustaining regional cooperation with focus on counter-terrorism measures, the army said.
Meanwhile, a Japanese destroyer and two more training ships have arrived in Sri Lanka to engage in a joint exercise with this country's navy.
"Matsuyuki", the destroyer which is 130 metres in length, and training ships "Kashima" and "Shimayuki" would take part in the joint exercise with Sri Lankan Navy's "Samudura" before leaving on September 19, Naval spokesman Kosala Warnakulasuriya said.