Washington (CNN) -- Reluctant approval from Congress for providing military support to Syrian rebels allows the Obama administration to move forward with plans first announced almost six weeks ago.
White House spokesman Jay Carney told reporters on Tuesday that the goal of the military aid expected to include small arms, ammunition and perhaps anti-tank weapons is to keep the Syrian opposition going against forces aligned with President Bashar al-Assad's regime.
Noting al-Assad's forces have been helped by Hezbollah in Lebanon as well as Iran, Carney said Syrian rebels need the help of the United States and allied nations to withstand an increased assault.
"The aid is intended to help the opposition resist Assad and eventually prevail," Carney said, adding that any resolution of Syria's civil war will require a political transition.
His comment appeared intended to soften any expectations that the rebels could topple the regime by military means alone.
A source, speaking on condition of being identified only as an official, said Monday that President Barack Obama can begin acting on plans for increased Syrian aid first made public last month now that concerns of Congress had been resolved.
House Intelligence Committee Chairman Rep. Mike Rogers said Monday that his panel agreed to the administration's plan for military aid despite reservations about its chances for success.
"After much discussion and review, we got a consensus that we could move forward with what the administration's plans and intentions are in Syria consistent with committee reservations," the Michigan Republican said.
At a congressional hearing on Tuesday on next year's defense budget, GOP Rep. Rich Nugent of Florida said he worried that arming Syria rebels today could mean his sons in the military might face those weapons in the future, if they fall into the wrong hands.
"We want to make sure that we don't put our sons or daughters in any jeopardy particularly as it relates to arming those that we have no idea who they are," Nugent said.
The Obama administration has been reluctant to enter another military engagement, but announced on June 13 that it would provide military support to rebel fighters because al-Assad's forces had used chemical weapons.
Its plans so far stop short of calls by some in Congress, such as veteran Republican Sen. John McCain of Arizona, to establish a "no-fly" zone over Syria.
In a letter released Monday, Joint Chiefs Chairman Gen. Martin Dempsey warned U.S. military involvement would likely cost billions of dollars and include a range of risks for the forces involved.
"It is no less than an act of war," Dempsey wrote to Democratic Sen. Carl Levin of Michigan, who chairs the Senate Armed Services Committee.
The United States has learned from the past 10 years "that it is not enough to simply alter the balance of military power without careful consideration of what is necessary in order to preserve a functioning state," Dempsey's letter said in apparent reference to wars in Iraq and Afghanistan.
McCain, who has long advocated arming Syrian rebels, said Tuesday he was disappointed by Dempsey's letter.
"Most military experts that I know totally disagree" with Dempsey's assessment of the size of the task and U.S. capabilities, McCain said. "The question should be is the status quo acceptable and obviously that is not."
Last month, McCain called for taking out al-Assad's air assets to create a safe zone for the Syrian opposition.
"I know that we have the military capability to impose a 'no-fly' zone, to crater their runways and their fixed installations where fuel and parts are, and establish a 'no-fly' zone with Patriot missiles," McCain said in June.
"And if we can't do that, then the question ought to be asked to the American taxpayer, to the Pentagon, 'What in the world are we wasting tens of billions of dollars for defense for if we can't even take care of this situation?'" McCain said.
More than 100,000 people have been killed since the Syrian crisis began in March 2011, while refugees fleeing the conflict threaten to overtax government services and destabilize neighboring Jordan.
In Washington, Secretary of State John Kerry met Tuesday with U.N. agencies and other international aid organizations to discuss challenges to addressing what he called a humanitarian crisis.
"We are having a very difficult time being able to access people, move people directly and protect people so we intend to have a very solid, in-depth discussion today about creative ways that we can meet our obligations to human beings who are in huge danger and distress," Kerry said.
He noted his visit this week to a Syrian refugee camp in Jordan where he said he witnessed "the dramatic and unbelievably moving ways in which people are separated from homes and family, so many people murdered and killed in massacres and yet somehow these people try to pull themselves together."
CNN's Jamie Crawford contributed to this report.