WASHINGTON -- Humanitarian groups are lobbying hard against a proposal by several U.S. senators that would turn over the delivery of millions of dollars in U.S. aid to a Syrian opposition council that’s criticized as too weak and too political to handle the responsibility.

Sen. John McCain, R-Ariz., is leading the charge to require the Obama administration to give the Syrian Opposition Coalition responsibility for aid delivery. The proposal was made after a bipartisan Senate delegation visited the region last month and heard firsthand Syrians’ frustrations with the pace and scope of U.S. and other foreign assistance.

The senators recommended that the Obama administration step up its support for the coalition so that the body “can visibly play a meaningful role in delivery of U.S. humanitarian aid.”

Executives from leading international aid groups are urging Congress to reject the recommendation. They say the proposal risks the traditional neutrality of aid missions and would place delivery of aid in the hands of an organization with no network for delivering it.

“The issue is whether or not we start turning aid into a political tool for the West,” said one humanitarian aid executive who met with members of Congress in recent days to discuss the issue. “Aid should be impartial, aid should be neutral, and aid, frankly, should be delivered with organizations that have the capacity to be accountable as well as able to get it there in the most efficient manner.”

The executive was one of three humanitarian aid officials from different agencies who met with McClatchy to discuss the issue on condition of anonymity because of the security and political sensitivities of their work in Syria.

In late January, the Obama administration announced that it would contribute another $155 million to aid Syrians displaced by the conflict in their country, bringing to $365 million the U.S. commitment to date.

The tug-of-war over how that aid is delivered – and by whom – is just one facet of a complex and worsening humanitarian crisis that affects millions of Syrians – many of whom are living in areas of the country that are difficult to reach.

The aid executives acknowledge that they have been able to reach only a fraction of the Syrians in need. But they warn that conditions could be far worse should Congress legislate the handover of aid delivery to opponents of Syrian President Bashar Assad.

Many members of the opposition coalition, the aid officials said, hail from the political elite that ruled Syria before or in the early days of the Assad dynasty. With their loyalties to disparate religious sects, political ideologies and regions of the country, the leaders could hardly be described as neutral. The main concern among aid workers is that the opposition would create a patronage system, steering goods to their own factions and stripping the veneer of neutrality from the process.

“I’m not calling into question their integrity,” one of the humanitarian officials said of the opposition leaders, “but how much can they resist the temptation of directing aid toward different agenda items?”

“We’re worried about a situation where decisions about aid are not based on vulnerability, but are being based on other factors, patronage and so on,” added another. “From a humanitarian perspective, that’s a dangerous road.”