The White House on Monday insisted it was leading the response effort to the humanitarian crisis in Syria, as the administration faces new questions about whether it has done enough to address the carnage in the war-torn country.

White House press secretary Jay Carney fended off questions Monday on whether the U.S. government had become “powerless” or was “losing” in its bid to limit the death toll from the brutal civil war between strongman Bashar Assad's regime and anti-government rebels.

Syria has seen a recent uptick in violence -- and the U.S. cut off aid to rebels in Northern Syria over concerns the assistance would fall into the hands of extremists.

Carney told reporters that the halting of aid would not affect humanitarian support, insisting that U.S. officials were providing more resources for the Syrians than any other nation.

“There is no resolution to the conflict in Syria without a negotiated, political solution,” Carney said. “There’s no question the situation there has been and is terrible.”

He later added, “There's no question that it's difficult, and Assad continues to brutally murder his own people.”

The White House has been hammered for being slow to react to the civil war in the heart of the Arab Spring.

When Obama ultimately called for intervention in Syria, Congress rebuffed his blueprint. Since then, the situation on the ground has not improved despite White House efforts to disarm Assad'schemical weapons arsenal.

The United Nations is also launching a new appeal for humanitarian aid to help Syria’s 2.3 million refugees, with an additional 6.5 million who have been displaced within the country.

The international body has requested $5 billion in aid -- $3 billion for refugees and $2 billion for those still in the war-ravaged country. A report in the Washington Post said that the U.S. has donated $1.4 billion, but that the U.N. is only two-thirds of the way to their goal.

The UN has begun dropping relief supplies in the north of the country, but aid groups are warning the humanitarian crisis will grow worse as winter sets in and are calling on the Obama administration and western countries to do more.

This story was published at 2:41 p.m. and has been updated.