File photo of US Secretary of State John Kerry. (AFP photo)
US Secretary of State John Kerry on Tuesday called on lawmakers to back a new three-year legal authorization supporting American military action against Islamic State militants.
The US-led coalition has already carried out some 1,100 airstrikes in Syria and Iraq since September targeting IS extremists in a bid to defeat the group which has seized a swathe of territory and imposed harsh Islamic law.
Under the US constitution, Congress has the ultimate power whether to declare war.
And so far the administration of President Barack Obama has used the existing authorization for use of military force against Al-Qaeda, the Taliban and their branches approved in the days after the September 11, 2001 attacks as the legal justification for going after IS.
Kerry insisted that the Obama administration had been empowered to target the Islamic State group under the existing law.
But he told the Senate Foreign Relations committee: "I think we all agree that this discussion must conclude with a bipartisan vote that makes clear that this is not one party's fight against ISIL (IS), but rather that it reflects our unified determination to degrade and ultimately defeat ISIL."
"Our coalition partners need to know it. The men and women of our armed forces need to know it. And ISIL's cadres of killers, rapists, and bigots need to understand it."
He asked the committee to help draw up a new authorization which "provides a clear signal of support for our ongoing military operations against ISIL," referring to the group by another acronym.
Kerry also urged that the text should not limit US actions geographically to just Syria and Iraq, and suggested it should be valid for three years with room for a possible extension.
Contingencies 'impossible to foresee'Controversially, the top US diplomat also appealed to senators not to rule out the use of ground troops.
Obama has insisted he will not send US ground troops into combat operations against IS, saying that "will be the responsibility of local forces."
"That does not mean we should preemptively bind the hands of the commander-in-chief -- or our commanders in the field -- in responding to scenarios and contingencies that are impossible to foresee," Kerry said.
While the Obama administration did not plan to carry out any operations with the 60-strong coalition outside of Syria and Iraq, Kerry argued the new legal authority should "not constrain our ability" to act in other places if needed.
"In our view, it would be a mistake to advertise to ISIL that there are safe havens for them outside of Iraq and Syria," he told senators.
Kerry also said that "we understand... the desire of many to avoid a completely open-ended authorization."
Committee chairman Bob Menendez has suggested a three-year limitation and "we support that proposal, subject to provisions for extension," the top US diplomat said. But he suggested that there needed to be more flexibility in the text.