Clinton unveils infrastructure plan

Hillary ClintonHillary Rodham ClintonSessions says he doesn't regret recusing himself from Russia probe Judiciary Committee Republicans want a second special counsel: report Fusion GPS: White House trying to smear us on Russia MORE on Sunday previewed her plan to rebuild America’s infrastructure.

"To build a strong economy for our future, we must start by building strong infrastructure today," the Democratic front-runner said at a campaign event in Boston, according to CBS News.

"I don't have to tell you what a sorry state we're in," she added. "Our roads and bridges are potholed and crumbling. Families endure blackouts because our electric grid fails in extreme weather."

More details are expected to be released on Monday.

Republicans have called the plan irresponsible, noting that Clinton has now proposed more than $1 trillion in new spending.

“With Hillary Clinton’s spending binge already at a trillion dollars and counting, it’s clear she wants to treat Americans’ tax dollars like every day is Black Friday with no plan to pay the bill,” Republican National Committee (RNC) spokesman Michael Short said in a statement on Sunday.

Clinton’s spending plan comes amid challenges in the Democratic primary from Sen. Bernie SandersBernie SandersLive Coverage: Senate edges close to passing scaled-down ObamaCare repeal Sanders: Senate healthcare fight 'totally bananas' Overnight Defense: Military won't lift transgender ban until Trump sends directions | House passes national security spending | Russian sanctions bill heads to Trump MORE (I-Vt.) and former Maryland governor Martin O’Malley, both of whom have campaigned on platforms they say are more progressive.

This report was updated at 4:43 p.m.