Re: the truce offer
Osama bin Laden offered a truce to comply with Koran requirements that before attacking an enemy who does not accept Islam, a truce must be offered.
I was just about to say the same thing.
I don't know much about the requirement, but I do know that Mehmed II made a truce type of offer before conquering Constantinople.
Osama had been criticized for attacking without making such an offer, so he offered Europe a truce about a year before the bombings in London.