It looks increasingly likely that Hillary Clinton will be named the Democratic nominee for president.
The former secretary of state won four of the five states voting on Tuesday night, dealing another blow to her rival, Vermont Senator Bernie Sanders.
Clinton won primaries in Connecticut, Delaware, Maryland and Pennsylvania on Tuesday night and will add significantly to her delegate lead over the Vermont senator.
Sanders, meanwhile, was declared the winner in Rhode Island just before 9:15pm with a 55-43 percent lead and 99 percent of precincts reporting their votes. But the small state does not carry many delegates, just 33, and will not help him to overcome Clinton's growing delegate lead.
The Connecticut race was a nail-biter, with news networks having to wait more than two hours after the polls closed on Tuesday before calling the race for Clinton. She defeated Sanders 55-43 percent, in the hotly contested state, with 100 percent of precincts reporting.
Clinton's victory in Maryland was strong enough that news networks called the race for her just as polls closed at 8pm, before official results began to trickle in. The state carries 118 delegates and a majority of them will go to Clinton's campaign. As Clinton took the stage to thank supporters on Tuesday night, she led Sanders by a stunning 37-points in the state. Clinton held a 63-33 percent lead in with 99 percent of precincts reporting.
Clinton also won Delaware on Tuesday night, one of the three states that the Sanders campaign had targeted. Clinton leads Sanders with a whopping 60-39 percent margin in the state, with 100 percent of precincts reporting their results.
Clinton appears to have notched a significant victory in Pennsylvania as well with a double-digit lead over Sanders. With 100 percent of precincts reporting, she held a 56-44 percent lead. Both she and Sanders campaigned hard in the state in recent days and the senator and his team had pointed to Pennsylvania as a state that they could potentially upset expectations. But Clinton is poised to take a majority of the state's 189 delegates.
Five states across the Northeast voted Tuesday — Connecticut, Delaware, Maryland, Pennsylvania, and Rhode Island — with Clinton holding large leads in recent polling in nearly all of them. Delaware and Rhode Island presented Sanders' best chances for victory on Tuesday, but were also the smallest states voting, carrying a total of just 64 delegates.
Clinton's victories on Tuesday night will make it much more difficult for Sanders to win the nomination. He began the evening trailing Clinton by 244 delegates and needing 1,181 more to clinch the nomination — and that's without counting superdelegates.
There are 14 contests remaining in the Democratic race, carrying a total of 1,206 delegates. Sanders will need almost all of them to get to the 2,383 that he would secure the nomination outright. Before any of Tuesday night's results are factored in, Clinton's 518 superdelegates put her just 419 short of that goal, while Sanders has just 39 superdelegates.
Clinton made it clear in her victory speech in Philadelphia on Tuesday night that she no longer considers Sanders to be her main rival. With the Vermont senator now firmly in her rearview mirror, Clinton shifted her focus to Donald Trump and the general election.
"I applaud Senator Sanders and his millions of supporters for challenging us to get unaccountable money out of our politics and giving greater emphasis to closing the gap of inequality," Clinton said. "I know that together we will get that done."
Clinton made several conciliatory nods to Sanders's base, while emphasizing the need for "bold progressive goals, backed up by real plans."
"After all," Clinton continued, "that's how progress gets made — we have to be both dreamers and doers."
The former secretary of state also repeated some favorite campaign lines indirectly calling out Trump for his hardline, anti-immigration rhetoric. "Instead of building walls, we're breaking down barriers," she said, before ending with the reminder that "Love trumps hate."
Although Sanders managed to peel a small number of delegates away from Clinton on Tuesday night, his path to winning the nomination by the July convention remains full of obstacles. He still trails his rival significantly in the delegate race and is facing growing pressure to drop out of the race from many Democrats.
Sanders has rebuffed those calls to end his bid for the Democratic nomination, although Tuesday's defeat could be the final nail in the coffin for his already-battered campaign. He suffered a 16-point loss in New York last week, causing him to decamp to his native Vermont to "recharge."
As primary voting was underway on Tuesday, Sanders's top strategist, Tad Devine, told the New York Times that the campaign will "reassess" their prospects after the primary and decide how to continue, though he stressed that the senator would compete in all of the remaining primaries.
"If we are sitting here and there's no sort of mathematical way to do it, we will be upfront about that," Devine said. "If we don't get enough today to make it clear that we can do it by the end, it's going to be hard to talk about it. That's not going to be a credible path. Instead, we will talk about what we intend to do between now and the end and how we can get there."
Devine said that if the campaign performed poorly on Tuesday night, they would have to shift away from trying to win the nomination based on pledged delegates. The campaign has previously discussed convincing superdelegates to flip their votes at the convention, though such a switch would be virtually unheard of if Sanders doesn't hold a lead in either pledged delegates or the popular vote.
Sanders and his wife, Jane, vehemently denied that the senator would consider dropping out anytime soon in a series of interviews on Tuesday.
"Since Iowa, we have been asked at every election, 'Are you getting out now'?" Jane Sanders said on MSNBC on Tuesday afternoon. "No, the answer is no. We're in it to the convention."
In an appearance on CNN, Sanders acknowledged that if Clinton were to perform well on Tuesday night, it would narrow his chances of winning the nomination. But he said he would not give up.
"Yes, it's a narrow path, but we do have a path," Sanders said. "And the idea that we should not contest in California, our largest state — let the people of California determine what the agenda of the Democratic Party is and who the candidate for president should be — is pretty crazy. So we're in this until the end."
Sanders congratulated Clinton on her victories in a statement late Tuesday night, committing to compete in all 14 remaining contests. Sanders reminded supporters that Rhode Island, where he won on Tuesday night, was the only state voting with a completely open primary that allowed independents to cast ballots.
"Democrats should recognize that the ticket with the best chance of winning this November must attract support from independents as well as Democrats," he said.
Sanders added that his campaign would continue to the end in order to allow Americans in every state to say "who they want as president and what the agenda of the Democratic Party should be." Significantly, Sanders said that his campaign would go all the way to the party's convention in July "with as many delegates as possible" in order to "fight for a progressive party platform" that includes many of his policy priorities, such as a $15 minimum wage.
The candidates will next face off in Indiana on May 3, when 92 delegates are up for grabs. Clinton holds a slight, single-digit lead in the Hoosier State.
Sarah Mimms contributed to this story.
Follow Olivia Becker on Twitter: @oliviaLbecker
This story is breaking and will be updated.