Rolling out her plan to defeat the Islamic State in the aftermath of the Paris terrorist attack, Clinton called for a "more effective coalition air campaign, with more allied planes, more strikes and a broader target set."

In her major policy speech on IS, Clinton told a New York audience that the US strategy should have three main elements.

"One: defeat ISIS in Syria, Iraq and across the Middle East. Two: disrupt and dismantle the growing terrorist infrastructure that facilitates the flow of fighters, financing arms and propaganda around the world. Three, harden our defenses and those of our allies against external and homegrown threats," she said in her address to the Council on Foreign Relations (CFR), a top American think-tank.

A key obstacle standing in the way is a shortage of good intelligence about ISIS and its operations. "So we need an immediate intelligence surge in the region, including technical assets, Arabic speakers with deep expertise in the Middle East and even closer partnership with regional intelligence services," she said. Clinton called for intensification of counter-terrorism effort.