[RusIvan]

I think that terrorist attacks are always made on noncombatants. It is a strike against a civilian target. Attacking military assets are military assaults. People who use unconventional and stealthy means to kill military assets are guerilla not terrorist.
Consider that the US used guerilla tactics in its own revolutionary war. According that article those revolutionary fighters were "terrorists". But it is wrong they was guerillas.

[American in Israel]

It is terrorism because if it is a military attack Israel would have the right to fight back. So it is terrorism. So says the UN.

[berserker]

In this recent undated image released by the Islamic militant group Hamas Sunday June 8, 2003, the three gunmen that carried an attack early Sunday at an Israeli army outpost in the Erez crossing between the Gaza Strip and Israel, pose dressed in military fatigues in an undisclosed location in the Gaza Strip. The three Palestinians, disguised as Israeli soldiers, sneaked into the army post Sunday and killed four soldiers before being killed by troops. The book they are holding is unknown.(AP Photo/HO)