• Photos

Secretary of State Hillary Clinton and Middle East envoy George Mitchell, right, arrive at the opening session of the Gaza reconstruction conference in Egypt Monday. (AP Photo)

Lawmakers on Capitol Hill say they are concerned that some of the billions of dollars pledged to rebuild the Gaza Strip, including money from the United States, may end up in the hands of Hamas. 

Egyptian Foreign Minister Ahmed Aboul Gheit announced at an international donors conference on Monday that $4.48 billion in new funds has been pledged for rebuilding the Gaza Strip, which was devastated in Israel's recent offensive against its Hamas rulers. He said other nations recommitted themselves to funds they promised in the past but never delivered, bringing the total to $5.2 billion. That includes $900 million from the United States, two-thirds of which would be directed to the West Bank-based Palestinian Authority. 

But the State Department said any money not going directly to the Palestinian Authority would be funneled to Gaza through international organizations and agencies, raising questions about whether those channels can keep the money out of Hamas' hands. 

"To route $900 million to this area, and let's say Hamas was only able to steal 10 percent of that, we would still become Hamas' second-largest funder after Iran," U.S. Rep. Mark Kirk, R-Ill., told FOXNews.com. Kirk called the overall package an apparent "waste of money," given the U.S. recession. Hamas, which the United States considers a terrorist organization, rules the Gaza Strip. 

State Department spokesman Gordon Duguid said Monday that the Gaza support would be provided through USAID, in coordination with United Nations agencies and other international organizations. And it's likely that among them would be the United Nations Relief and Works Agency -- which has been accused of allowing terrorist propaganda in classrooms it funds and has suffered several high-profile examples of terrorist leaders who were on the agency's payroll. 

Most recently, UNRWA handed Sen. John Kerry, D-Mass., a letter addressed to President Obama from Hamas. The group apparently did not tell Kerry the letter was from Hamas, but later told media outlets that it was -- outraging U.S. officials. 

"This aid relief package would be unique in its complete lack of transparency," Kirk said. "If assistance is provided through reputable foreign aid mechanisms that allow outside audits, support on the Hill would build. But if it goes thru UNRWA, which has not had an outside audit, then there's going to be grave concern." 

Several offices have been informally discussing the possibility of avoiding UNRWA altogether and routing the money through the United Nations Development Programme instead. 

Over 45 House members have signed a letter from Kirk and Reps Steve Rothman, D-N.J., to Secretary of State Hillary Clinton demanding an outside audit of UNRWA. 

Clinton, who is on her first foray into Middle East diplomacy, declared the Obama administration has committed to working intensively to find a way for Israelis and Palestinians to exist peacefully in separate states. She used the international donors conference to issue a blunt call for urgent action to forge a comprehensive Arab-Israeli peace, and she said American aid will not end up in the wrong hands. 

"We have worked with the Palestinian Authority to install safeguards that will ensure our funding is only used where and for whom it is intended and does not end up in the wrong hands," Clinton told the conference. She did not mention Hamas, but she alluded to extremist elements. 

"It is time to break the cycle of rejection and resistance," she said, "to cut the strings pulled by those who exploit the suffering of innocent people." 

But even if the donors bypass Hamas, as is likely, it would benefit from any aid that eases pressure on it to help the needy. 

And even money given by the U.S. through its own entities is not guaranteed to stay out of the hands of terrorists. 

In 2007, Congress changed the laws governing foreign aid after learning that USAID had been funding the Hamas-controlled Islamic University in Gaza. Lawmakers moved to enhance restrictions on aid to any group that has advocated or supported terrorism, or that has a leader in the organization who has done so. 

Meanwhile, Clinton said Monday that President Obama would continue the Bush administration's focus on seeking a two-state solution that entails Israel and a sovereign Palestinian state co-existing peacefully. 

"It is time to look ahead," she said. "The United States is committed to a comprehensive peace between Israel and its Arab neighbors, and we will pursue it on many fronts."  

Clinton is scheduled to travel to Jerusalem this week to consult with Israeli officials and to the West Bank to meet with Palestinian officials. She gave no breakdown of the U.S. funding for the region, but her spokesman, Robert A. Wood, said on Sunday that it included $300 million in humanitarian aid for Gaza and about $600 million in budget and development aid to the Palestinian Authority. 

Clinton stressed that the Obama administration is taking a wide-angle view of the humanitarian crisis in Gaza following weeks of attacks by Israel in response to Hamas rockets fired into southern Israel. 

"Only by acting now can we turn this crisis into an opportunity that moves us closer to our shared goals," she said. 

"By providing humanitarian aid to Gaza we also aim to foster conditions in which a Palestinian state can be fully realized, a state that is a responsible partner, is at peace with Israel and its Arab neighbors and is accountable to its people," she added. 

FOXNews.com's Joel Mowbray and The Associated Press contributed to this report.