There can be no correlation between the acts of terrorism and Islam. Allah the Almighty regulates Muslims’ relations with Non-Muslims in the verses below:
“Allah does not forbid you from being kind and equitable to those who do not fight you because of religion and do not expel you from your homes and do not help them (in this fight and expulsion). Indeed, Allah loves those who are equitable. Allah only forbids you from making friends of those who fight you because of religion and expel you from your homes and aid in your expulsion. The ones that make friends of them are the wrongdoers.” (Al-Mumtahenah / The Examined One 60:8-9)
According to these verses, Muslims are only forbidden to make friends with the non-Muslims that fight Muslims because of their religion, that expel them from their homes or that who aid in their expulsion; let alone the acts of terrorism!
One who believes and regulates his life according to these verses cannot be in any part of acts called terrorism.
Please also see:
Is Islam a religion of war or peace?: http://www.islamandquran.org/fatwas/is-islam-a-religion-of-war-or-peace.html
Relations with non-Muslims: http://www.islamandquran.org/fatwas/relations-with-nonmuslims.html