Donald Trump accused Hillary Clinton of "playing the woman card" in her presidential campaign as he prepared for a general election showdown with the Democratic front-runner.
Mr Trump swept five states in Tuesday's primaries, bringing him close to securing the Republican nomination against Texas senator Ted Cruz and Ohio governor John Kasich.
Mrs Clinton, meanwhile, is now 90 per cent of the way to her party's nomination after four solid victories of her own.
Mr Trump, the Republican businessman, pushed forward with his charge that Mrs Clinton is "playing the woman card", telling CNN's New Day that "she does have the woman card" but said that "a lot of women don't like Hillary, despite the card".
Mrs Clinton said during her rally in Philadelphia on Tuesday night that "if fighting for women's health care and paid family leave and equal pay is playing the 'woman card', then deal me in".
The Republican race now turns to Indiana, where next week's primary marks one of Mr Cruz's last chances to slow Mr Trump and push the race towards a contested convention.
While Mr Trump does need to keep winning in order to stay on his narrow path to the GOP nomination, he declared himself the party's "presumptive nominee" after Tuesday's results rolled in.
"It's over. As far as I'm concerned it's over," he said.
The real estate mogul now has 77 per cent of the delegates he needs.
Mr Trump emerged with more than 50 per cent of the Republican votes in Pennsylvania, Connecticut and Maryland, and scored over 60 per cent in Delaware and Rhode Island.
Similarly, Mrs Clinton won convincingly in four of the five contests, scoring 56 per cent in Pennsylvania and 63 per cent in Maryland - the two biggest contests of the night.
Her rival, Vermont Senator Bernie Sanders, won the Rhode Island primary with 55 per cent of the vote.
Mr Trump planned to deliver a foreign policy speech in Washington and then campaign in Indiana.
The address is the first in a series of speeches the Republican front-runner is expected to give in the coming weeks, all with the goal of easing Americans' concerns about his readiness for the presidency.
Likewise, Mrs Clinton was eager to turn her attention to Mr Trump.
While her advisers say they will not underestimate Mr Trump, as many of his Republican rivals did, her campaign sees opportunities to not only energise Democrats in an effort to keep him out of the White House but also appeal to Republicans turned off by the brash billionaire.
"If you are a Democrat, an independent or a thoughtful Republican, you know that their approach is not going to build an America where we increase opportunity or decrease inequality," Mrs Clinton said of the GOP candidates.
Mr Sanders, meanwhile, conceded he has a "very narrow path and we're going to have to win some big victories".
In the Republican race, Mr Cruz and Mr Kasich are desperately trying to force a convention fight.
The challengers have even taken the rare step of announcing plans to co-ordinate in upcoming contests to try to minimise Mr Trump's delegate totals.
But that effort did little to stop Mr Trump from a big showing, picking up at least 105 of the 118 delegates up for grabs. He now has 950 of the 1,237 delegates he needs to secure the nomination.
Mrs Clinton now has 2,141 delegates while Mr Sanders has 1,321.
