outbreak (of war etc.)

to break out

a land, a large place / a country in general, a region / a country as in a nation, a state / the office of emperor, the crown; affairs of state / a province of ancient Japan

war (conflict involving organized use of arms)

to wage war

countries

a land, a large place / a country in general, a region / a country as in a nation, a state

national / country

The War in Iraq; the Iraq War

nuclear war