WASHINGTON — Pressure is mounting on Bernie Sanders to end his campaign for president, with Democratic Party leaders raising alarms that his continued presence in the race is undermining efforts to beat presumptive GOP nominee Donald Trump this fall.

The new concerns come after Sanders’ recent wins over front-runner Hillary Clinton in Indiana and West Virginia. While those victories have provided his supporters a fresh sense of momentum heading into next week’s primaries in Kentucky and Oregon, they did almost nothing to help Sanders cut into Clinton’s nearly insurmountable lead in the delegates who will decide their party’s nomination.

“I don’t think they think of the downside of this,” said Sen. Dianne Feinstein, D-Calif., a Clinton supporter who hosted the 2008 meeting that brokered post-primary peace between Clinton and then-Illinois Sen. Barack Obama.

“It’s actually harmful because she can’t make that general-election pivot the way she should,” Feinstein said. “Trump has made that pivot.”

Clinton, her aides and supporters have largely resisted calling on Sanders to drop out, noting that she fought her 2008 primary bid again Obama well into June. But now that Trump has locked up the Republican nomination, they fear the billionaire businessman is capitalizing on Sanders’ decision to remain in the race by echoing his attacks and trying to appeal to the same independent, economically frustrated voters that back the Vermont senator.

“I would just hope that he would understand that we need to begin consolidating our vote sooner rather than later,” said New York Rep. Steve Israel, a Clinton backer and former chief of efforts to elect Democrats to the House. “Democrats cannot wait too long.”

Though Clinton has for the past few weeks largely focused her rhetoric on Trump, campaign aides said the two-front effort hampers their ability to target both Sanders supporters and Republican-leaning independents that may be open to her candidacy. It also means she’s spending time in primary states, rather than battlegrounds that will decide the general election.