Military experts believe 2017 will be a difficult year for the American military in the Pacific area.

　　They note that China has become more aggressive in the area and that countries like the Philippines and North Korea are also a threat.

　　Michael O'Hanlon studies military issues at the Brookings Institution, a research group.

　　"North Korea, President Obama has just said to Mr. Trump, that this is in fact perhaps the sort of least-appreciated danger out there."

　　Experts say North Korea is building up to six nuclear weapons each year. A senior U.S. military official says North Korea now has the ability to launch these weapons, although the warheads may not yet be able to hit a set target.

　　The Philippines has been an ally of the United States for many years. But Philippine President Rodrigo Duterte has sought to limit ties with the U.S. since taking office earlier this year.

　　U.S. Navy and Marine officials have told VOA they will not take part in joint defense training exercises with the Philippine military. They will only train for disaster relief.

　　U.S. Army Lieutenant General Stephen Lanza says the Army may also change its planned training with the Philippine military next year -- from combat preparation to humanitarian assistance.

　　"We're still working with the Philippines right now. We may have to make some adjustments based on operations in the Philippines, and we're prepared to do that."

　　The U.S. still has a large military presence in the Pacific. The Navy has four aircraft carriers in the area. The Army is taking part in military exercises with South Korea, the Philippines, Thailand and, for the first time, Cambodia.

　　Lanza says Vietnam has also asked to take part in the exercises.

　　"You want to be there to deter. You want to be there to avoid conflict and, really, to avoid miscalculation. And I know our partners appreciate the fact that we are engaged with them in the Pacific."

　　Lanza says the militaries of many countries should work together to prepare for difficult times.