The U.S. Conference of Catholic Bishops has expressed its concerns over proposed cuts in federal programs serving the country's poorest and most vulnerable people in a series of letters to congressional leaders.

The letters urge Congress to draw a "circle of protection" around programs that serve "the least among us."

The letters were sent after the House of Representatives adopted on March 27 a $3.5-trillion budget resolution – with a $600 billion deficit.

The plan calls for massive spending cuts in non-military programs.

A common message in the letters focuses on the necessity of "shared sacrifice by all, including raising adequate revenues," the elimination of unnecessary military and other spending and fairly addressing long-term costs associated with health insurance and retirement costs.