WASHINGTON (AP) — Lawmakers must pass legislation easing the "abhorrent conditions" facing children held at the southern border, House Speaker Nancy Pelosi said Monday as she tried taking the offensive on an issue that badly split Democrats and has raised questions about their unity on other issues.

In a letter to colleagues returning from a weeklong Fourth of July recess, Pelosi said Democrats must lead "a Battle Cry across America to protect the children."

Before Congress left town, legislators used lopsided margins to approve a $4.6 billion border bill that President Donald Trump signed into law. But the measure left a bitter rift between moderates and liberals and between House and Senate Democrats, with many House progressives and Hispanics voting "no," asserting that the measure lacked strict standards of care for children.

While Pelosi's letter didn't promise action on any particular bill, she highlighted several measures that liberal and Hispanic Democrats have pushed. These included proposals barring separation of families unless it is to protect children, requiring specific standards of care like thorough medical screenings, and limiting how long unaccompanied children may be kept at temporary holding facilities, many of which are overcrowded.

The note from Pelosi, D-Calif., came amid uncertainty about the mood of House Democrats as they return Tuesday from their break.

Before leaving, many liberals and Hispanic members expressed fury at some of the chamber's moderates, who rebelled and prevented Pelosi from having a vote on adding care requirements to the bill that was approved. Her letter seemed an effort to assuage her angry colleagues and refocus their attention on Republicans.

Citing another battle over blocking a citizenship question Trump wants to add to the census, Pelosi said, "In both the case of the Census and the abhorrent conditions for children and families at the border, we must hold the Trump Administration and the GOP accountable."