Are drone strikes an act of war?

When one country systematically targets another country for strategic bombing, is this considered an act of war or a police action. The US administration's reasoning is to target suspected terrorist cells as part of the "war on terror".
I do know that if someone was bombing my country, I would see this as an act of war. Additionally, these bombings are, and must be considered as, acts of terrorism.
Can someone please enlighten me?