AFP published this article:

South Korea and the United Stateskicked off their largest joint military exercises in five years on Monday, after nuclear-armed Pyongyang warned such drills could be seen as a "declaration of war".
Washington and Seoul have ramped up defence cooperation in the face of growing threats from the North, which has conducted a series of banned weapons tests in recent months.

The US-South Korea exercises, called Freedom Shield, are scheduled to run for at least 10 days from Monday and will focus on the "changing security environment" due to North Korea's redoubled aggression, the allies said.

In a rare move, the Seoul military this month revealed that it and Washington special forces were staging "Teak Knife" military exercises -- which involve simulating precision strikes on key facilities in North Korea -- ahead of Freedom Shield.

All such exercises infuriate North Korea, which views them as rehearsals for an invasion.

It has said its nuclear weapons and missile programmes are for self-defence.