(Cairo)  --   Troops are moving through the streets of Cairo after a deadline came and went for President Mohamed Mursi to share power.  A national security adviser says a military coup is underway.  The city's main square is jammed full of demonstrators.  Mursi held fast yesterday, saying he would not leave office.  

[PHOTOS: Protests in Egypt]

Meantime, U.S. oil prices are at a 14-month high above 100 dollars a barrel.  There's fear that continuing unrest in Egypt could lead to a supply disruption.  Egypt is the Arab world's most populous nation.