Despite diplomatic momentum, divisions within Tehran’s leadership continue to threaten prospects for a lasting agreement, the officials said.
‘There’s no oil blockade on Cuba per se,’ Secretary of State Marco Rubio told reporters.
The government must release allocated money to Gavi, the senators said.

The suspect is now facing prosecution for allegedly hiding illegal narcotics with an estimated street value of nearly $1.5 million.
Those arrested were charged for crimes including sexual exploitation, sex trafficking, abuse, kidnapping, and more.
The Education Department launched an investigation into Smith College in Massachusetts, which admits males and gives them access to spaces designed for women.
The tech company joins about a dozen other high-profile firms to reincorporate away from Delaware after a state court canceled Elon Musk’s pay package.
Trump endorsed GOP challengers in seven state Senate races where incumbents had opposed a congressional redistricting bid backed by the president.

Brown’s victory sets the stage for a general election clash with Republican Sen. Jon Husted, who is endorsed by President Donald Trump.
Sprague, the current state treasurer and a former state representative, held off a bid from combat veteran and former Air Force intelligence officer Strbich.
Taxes and health care policies were prominent issues for voters who spoke to The Epoch Times at three Columbus-area locations on May 4 and May 5.
It comes as Democrats say they are targeting eight more House seats.
U.S. Treasury Secretary Scott Bessent said, ‘China, let’s see them step up with some diplomacy and get the Iranians to open the strait.’
A federal judge previously said the case can’t move forward until the FDA completes its review of mifepristone.
‘Right now, it’s not working. It’s insufficient. I think it’s legally deficient,’ the judge said about the alleged assassin’s confinement.
House Democratic leader Hakeem Jeffries is dispatching Rep. Joe Morelle to meet with Gov. Hochul and legislative leaders this week.
The transportation chief predicted immediate pump relief once normal shipping resumes in the Gulf, even as oil markets remain volatile amid Iran tensions.
The escalating tensions follow Washington’s announcement of ‘Project Freedom’ to restore freedom of navigation in the strait.
Taxpayers have to act before July 10, said the IRS’s internal watchdog.
U.S., Moroccan, and partner forces involved in the multinational exercise immediately launched a search and rescue operation.
Health secretary says improving farmland soil is key to producing nutritious foods to fight chronic health issues.