WASHINGTON (AP) – Congressional liberals are telling the Obama administration that a health overhaul bill cannot pass unless it includes a new government-run insurance option.

The Congressional Progressive Caucus, made up of more than 80 liberal House members, wrote to Health and Human Services Secretary Kathleen Sebelius expressing opposition to her weekend comments suggesting a public option was not essential to a health overhaul.

Liberals insist a new public insurance plan is essential but Republicans almost uniformly oppose it.

White House Spokesman Robert Gibbs said Tuesday that the administration, which has supported a public plan, hasn’t changed its stance. The Progressive Caucus told Sebelius that taking the option off the table would be a “grave error.”