The Eiffel Tower stood dark in a symbol of mourning Saturday night as France struggled to absorb the deadliest violence on its soil since World War II: coordinated gun-and-suicide bombing attacks across Paris that left at least 129 people dead and 352 injured.<br />President Francois Hollande vowed that France would wage "merciless" war on the Islamic State of Iraq and Syria , which claimed responsibility for the mayhem , as investigators raced to track down their accomplices and uncovered possible links to networks in Belgium and Syria.<br />Seven attackers launched gun attacks at Paris cafes, detonated suicide bombs near France's national stadium and killed hostages inside the concert venue during a show by an American rock band - an attack on the heart of the pulsing City of Light.<br />Late Saturday, a crowd of up to 250 people gathered for an impromptu candlelight vigil at the Place de la Republique, the site of a massive demonstration in the wake of the Charlie Hebdo killings earlier this year.
