Senate Republicans say negotiations over a stalled disaster aid bill have largely broken down over an entrenched fight on additional funding for Puerto Rico, which has emerged as a sticking point for President TrumpDonald John TrumpTrump calls Sri Lankan prime minister following church bombings Ex-Trump lawyer: Mueller knew Trump had to call investigation a 'witch hunt' for 'political reasons' The biggest challenge from the Mueller Report depends on the vigilance of everyone MORE and Democrats. 
Sen. Richard ShelbyRichard Craig Shelby20 Dems demand no more money for ICE agents, Trump wall Conservatives urge Trump to stick with Moore for Fed Poll: Roy Moore leading Alabama GOP field MORE (R-Ala.), the chairman of the Senate Appropriations Committee, said Republicans had made a "serious" and "substantial" offer over the weekend, but it had been rejected by Democrats. 
"We … made a serious, substantial offer over the weekend to them that solved the disaster and they categorically rejected it. So we're at a standoff at the moment, and we'll wait and see what they come up [with]," Shelby said. 
Asked what was in the GOP offer, Shelby declined to comment except to say that it was "serious." 
The disaster aid bill, meant to respond to a recent spate of storms, hurricanes and wildfires, has been stuck in the Senate since last week, when lawmakers blocked competing proposals from getting the 60 votes needed to move forward.
The GOP bill, which Democrats blocked last week, included $600 million for food aid for Puerto Rico. 
A senior Senate Democratic aide told The Hill on Tuesday that the offer from Republicans over the weekend didn't guarantee new funding for Puerto Rico or make sure that money already allocated to the island territory would be disbursed to Puerto Rico. 
"Instead, the Republican plan inflates a pot of funding that all disasters can take from and says Puerto Rico is eligible only after it spends the funding that the administration is refusing to release," the aide continued. 
The source added that the GOP offer also does not include funding to help rebuild water systems in Puerto Rico, which was devastated by back-to-back hurricanes. 

Puerto Rico is the key sticking point on the fate of the disaster aid bill. Democrats are demanding extra help for the island, to mirror legislation passed by the House, but Senate Republicans warn that Trump will not sign such a bill. 
"We know the House, to their credit, is standing firm," he said. "We don't just say we'll give food stamps to some but complete disaster relief to others. That's wrong, and that hurts American citizens in Puerto Rico and elsewhere."
The president criticized the island and its handling of previous disaster relief money during a closed-door lunch with Republican senators late last month. 
Sen. John CornynJohn Cornyn Embattled senators fill coffers ahead of 2020 Trump struggles to reshape Fed Congress opens door to fraught immigration talks MORE (R-Texas), asked about the fate of the package after a closed-door GOP leadership meeting on Monday night, added that "it sounds like it's kind of not doing too well."