Sens. Marco Rubio (R-Fla.), Mark Kirk (R-Ill.) and Ben Cardin (D-Md.) are demanding that Secretary of State John Kerry launch an independent investigation into at least three incidents where Hamas rockets were discovered at facilities of the United Nations Relief and Works Agency (UNRWA).

The senators argued in a letter last week that the weapons were particularly troubling when coupled with anti-Israel statements and actions of the UN agency.

Their letter cites “multiple instances of weapons found at UNRWA schools as well one-sided statements from UNRWA leadership that unjustly condemn Israel,” including  UNRWA Commissioner General Pierre Krahenbuhl stating July 14 that Israeli security forces are acting “contrary to international humanitarian law” and conducting an “illegal” blockade of Gaza.

“As you know, UNRWA admitted on July 17th, July 22nd, and July 30th that it found rockets belonging to Hamas on its property. We commend UNRWA’s quick condemnation of these incidents, but are concerned with the ultimate fate of these rockets, which UNRWA claimed to have turned over to the  ’local authorities’ or have gone missing. We fear that this means these rockets may have found their way back into Hamas’ hands,” the senators wrote.

“We urge the State Department to launch an independent investigation into these incidents and to call on the United Nations leadership to hold UNRWA accountable, including by reprimanding or dismissing the UNRWA staff responsible as appropriate, as well as asking the U.N. to ensure that these incidents never take place again,” the letter continues. “In the course of your investigation, we ask you to examine the fate of these rockets, what measures the U.N. took to secure UNRWA property, and how the U.S. intends to work with the U.N. to make sure incidents like these are never repeated.”

“As you know, the United States is the largest donor to UNRWA and has contributed almost $5 billion to the organization since 1950. The United States taxpayers deserve to know if UNRWA is fulfilling its mission or taking sides in this tragic conflict.”

The 2013 U.S. contribution to UNWRA was $294 million. In September 2012 elections for UNRWA’s workers union board, Hamas-affiliated candidates won 25 out of 27 seats.

At the State Department last week, spokeswoman Marie Harf said “our folks are looking into” reports that UNRWA summer camps are teaching Palestinian kids to hate Jews and wage jihad.

“They didn’t have any clarity for me when I came out here, but I’ll follow up with them because obviously, look, any — any anti-Semitic language, any — any language like that really just has no place in the discourse about this or any other issue,” Harf told reporters.

“Given UNRWA’s ties to terrorism in the past, U.S. taxpayers deserve immediate answers and full transparency regarding their intentions and actions,” Kirk said in a statement. “The State Department must make clear to the U.N. that it needs to take all necessary steps to prevent Hamas from using taxpayer-funded property to launch terror attacks against our allies.”

“When leaders and organizations of the United Nations blur the clear distinction between a nation-state defending itself and a terrorist organization attempting to murder civilians, Americans take note,” said Cardin. “When an organization funded in part by the U.S. suggests that the two are morally equivalent, U.S. taxpayers take note.”