For the first time since launching his campaign, Donald Trump is now hitting 50 percent support among Republican and GOP-leaning voters.

A new NBC News national poll finds Trump has soared to a new high as the last several weeks of the 2016 primary season heads into high gear. Previously the bombastic businessman's support has hovered in the mid to high 40 percent range.

Among Republicans who now lean toward the GOP, Trump bags 49 percent support, an uptick of six full points over just the last week.

Trump Supports Rises, While Cruz and Kasich Slip

Meanwhile, support for Trump's two GOP rivals, Texas Sen. Ted Cruz (28 percent) and Ohio Gov. John Kasich (15 percent), is down by an average of two percent over that same time.

After recently sweeping primaries held in Pennsylvania, Rhode Island, Connecticut, Delaware and Maryland, Trump pronounced himself the GOP's "presumptive nominee."

"This to me was our biggest night," he added of the momentum his latest showing, coupled with his recent massive win in New York, seemed to bring his campaign.

Trump's big night made for at least an additional 142 delegates, bringing his overall total to 988, just 249 short of 1,237 he needs to secure the party's nomination outright. By comparison, Cruz and Kasich have just 720 combined.

Clinton Tops Sanders in Four of Five Primaries

Meanwhile, Hillary Clinton claimed wins over Bernie Sanders in Pennsylvania, Connecticut, Maryland and Delaware, bringing her delegate count to 2,168, just 215 short of the total she needs to formally bag the Democratic nomination.

In the aftermath, Sanders seemed to signal a change in strategy.

"The people in every state in this country should have the right to determine who they want as president and what the agenda of the Democratic Party should be," he said a statement. "That's why we are in this race until the last vote is cast. That is why this campaign is going to the Democratic National Convention in Philadelphia with as many delegates as possible to fight for a progressive party platform."

Despite winning at least 1,401 delegates, Sanders' campaign has struggled in closed primaries where independents are unable to vote.

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