I think the first course of action is for the Muslim countries to convoke an immedieate conference to deliberate this issue. Then they must take a collective decision, e.g., such as withdrawing their emissaries to Israel if they have any sort of diplomatic relations.
After which they should threaten an economic embargo, the type israel has imposed arbitrarily on Gaza. But the problem is, that these actions can only be done by a genuinely independent, progressive and concerned leadership. Which many nations in the Muslim world are bereft of, and are being governed instead, by tyrants preserved by american assistance. Everytime i cogitate about this, i keep coming back to this same point, which has now become a political point of reference for anyone seeking to know anything about passivity on the part of the arab regimes and it's ramifications for the Palestinians.