As U.N. officials say hospitals in Gaza are running dangerously low on fuel, Hamas is maintaining a stockpile of more than 200,000 gallons of fuel for the rockets it fires into Israel and the generators that provide clean air and electricity to its network of underground tunnels, according to U.S. officials, current and former Israeli officials and academics.

The statements come as President Joe Biden called for a humanitarian pause in Gaza and U.N. officials warned that aid agencies, water treatment plants and bakeries there may soon run out of fuel. Israel, which has allowed a limited number of trucks carrying food, water and medicine into the enclave, continues to ban deliveries of fuel, which it says Hamas will use for military purposes. 

 Hamas, meanwhile, has repeatedly demanded fuel deliveries to Gaza during negotiations to allow foreign nationals to leave the enclave and in talks regarding the release of 240 people it kidnapped.

 National Security Advisor Jake Sullivan said on CNN Sunday that Hamas has been blocking Americans from leaving Gaza. “Hamas has been preventing their departure and making a series of demands,” said Sullivan, who declined to describe the demands. Other U.S. officials said fuel deliveries was among the stumbling blocks. 

 In testimony to Congress on Tuesday, Secretary of State Antony Blinken said that Hamas is refusing to share its fuel with hospitals in Gaza. “Hamas has its own supply stockpile of fuel,” Blinken told the Senate Appropriations Committee. “If it cared a whit about the people of Gaza it would make sure itself that it used that fuel to have the hospitals be able to operate the incubators, stay turned on, etc. But, of course, it doesn’t.” 

Israeli military officials estimate that Hamas has roughly 200,000 gallons of diesel in storage. Experts say that the exact amount of fuel that the group is impossible to know.

“We don’t know how much they have, and we definitely don’t know how much they need, because no one is sure to what extent this underground city goes,” said Prof. Elai Rettig of Bar Ilan University in Tel Aviv who studies regional energy cooperation. “If it’s just for ventilation and basic communication, it will last for months.”

The Israeli Defense Forces released an intercept on Wednesday of a call between what it said was a commander of Hamas’s Western Jabaliya Battalion, a Gazan resident, and the director of the Indonesian Hospital in north Gaza. The commander said Hamas is taking fuel from the hospital’s stocks, according to the IDF. NBC News has not independently authenticated the call.

Current and former U.S, and Israeli officials agree that, even if Hamas is hoarding fuel, the international community has a responsibility to provide humanitarian aid to Gazan civilians. “We have an obligation to do everything we can, if Hamas is not going to do it, to look out for people in Gaza,” Blinken said. “So we are working on a mechanism that can give fuel to where it’s needed, particularly if it’s just hospitals, bakeries [and] desalination plants.”

More than 200 trucks of food, water, medicines and medical equipment have crossed from Egypt into Gaza since the start of the war, according to U.N. officials. But Israel has banned the delivery of fuel since Hamas’s Oct. 7th terrorist attack killed 1,400 people. 

“Israel is and should allow aid trucks into Gaza,” said Eyal Hulata, Israel’s former National Security Advisor. “But let’s call a spade a spade- it’s not in the interest of Hamas to have the international community see that Israel is doing that.  Israel is not blocking humanitarian aid into Gaza, it’s blocking the fuel Hamas needs to fight Israel.”

“There is no surprise that Hamas wants the fuel,” he added. “Hamas is interested in the resources to provide electricity in the tunnels and to fight Israel.”

The United Nations has issued almost daily warnings that UNRWA will not be able to operate humanitarian services including hospitals because they don’t have enough fuel. Humanitarian groups also say that not enough food, medicine and water is arriving  to meet the needs of Gaza’s 2.2 million people.

“While fuel is critical to easing the humanitarian crisis, Hamas has already demonstrated its willingness to steal fuel and humanitarian supplies from civilians,” said Jonathan Lord, a senior fellow and the director of the Middle East Security program at the Center for New American Security in Washington. 

“It’s yet another dilemma facing Israel and the international community,” he added, “stemming from Hamas’ willingness to put Gaza’s civilians in harm’s way to enable itself.”