WASHINGTON — The White House endorsed an emerging bipartisan agreement Monday on legislation aimed at curbing rising health care costs, including taking steps to limit “surprise” medical bills that can plague patients treated in emergency rooms.

While the deal’s fate remained uncertain, enactment could give President Donald Trump and lawmakers of both parties a chance to crow about a rare legislative achievement during a bitterly divisive period dominated by Democrats’ drive toward impeaching Trump.

House and Senate participants said the measure would establish a system of arbitration aimed at resolving disputes over surprise bills, which can occur when patients are unwittingly treated by providers from outside their insurance networks.

It would also raise the federal minimum age for buying tobacco products to 21 from its current 18, including for electronic smoking devices, aides said. It would provide $20 billion over five years to finance community health centers, which provide medical care to millions of lower-earning people in thousands of towns, and take steps toward limiting the growth of prescription drug prices.