The United States says the Indian Ocean is being used to transport weapons for terrorist groups.

Deputy US Assistant Secretary of Defense for South and Southeast Asian Affairs Robert M. Scher told a conference in the Sri Lankan southern city of Galle on Monday that the Indian Ocean has also become a transit hub for proliferaters.

He was attending a maritime security conference in Galle which also has participants from several other countries including China, India and Singapore apart from the hosts Sri Lanka.

"There are also more actors engaged in the Indian Ocean than ever before. These include nation states both in and outside the region, many of whom that are developing increasingly capable militaries. As a result, the US is taking a renewed look at how this region affects us and how we can best address our interests," the US Embassy in Colombo quoted Scher as saying.

He said that the proliferation of weapons of mass destruction across the Indian Ocean region is another challenge that threatens to undermine the peace and stability of the region.