A large explosion rocked a central square in Iran’s capital where thousands were gathered Friday for an annual state-organized rally to support the Palestinians and call for Israel’s demise. Israel had warned that it would target the area in central Tehran. There were no reports of casualties. But the decision to proceed with the mass demonstration that was attended by some senior government officials, and Israel’s threat to target the area, underscored the fierce determination on both sides nearly two weeks into a war that has rattled the global economy and shows no sign of letting up. Read moreMiddle East war live: Israel says forces carried out 7,600 strikes in Iran, 1,100 in Lebanon Meanwhile, a US official said that roughly 2,500 Marines and at least one amphibious assault ship were headed for the Middle East in a major addition of troops.  Iran has continued to launch widespread missile and drone attacks on Israel and neighboring Gulf states, and has effectively closed the Strait of Hormuz, through which a fifth of the world’s traded oil …