WASHINGTON — The Democratic speaker of the US House of Representatives vowed Thursday that lawmakers would approve a health care overhaul bill that includes a controversial government-run "public option" insurance plan.

The measure, fiercely opposed by minority Republicans, would compete with private insurance companies.

"We don't intend to go to the floor without a public option in that bill," Nancy Pelosi said at her weekly press conference. "I have said that the House bill will have a public option."

The comments come after a key US Senate committee on Tuesday defeated a proposal to include a "public option" plan in legislation to remake the way Americans get and pay for health care.

President Barack Obama, who has made overhauling US health care his top domestic priority, has said he supports the "public option," and many core Democrats say they will oppose a final plan without one.

Obama said he hopes to sign a health care reform into law by the end of the year.

A Senate panel and three committees in the House of Representatives have included a version of the proposal, which is also opposed by some swing-vote Democrats.

After health care reform legislation is approved in the House of Representatives, the bill must be reconciled with a version approved by the US Senate.

"What happens in the conference is another step," Pelosi said. "I'm confident though that if we go in with a public option, the public support will be overwhelming," she said.

The public option is supported by most senators from the Democratic majority.

Senate Majority Leader Harry Reid vowed: "We're going to do our very best to have a public option."

Another senior Democratic senator, Charles Schumer, said that he has talked to conservative Democratic senators "and they are open to some kind of public option."