Update: 2:42 p.m. Updated with new comments from Gov. Chris Gregoire.

OLYMPIA -- Gov. Chris Gregoire lashed out Monday afternoon at Attorney General Rob McKenna's decision to join a multistate lawsuit challenging the health-care legislation just approved by Congress.

Speaking to reporters before a bill-signing ceremony, Gregoire said McKenna hadn't consulted her or Democratic legislative leaders before making his announcement.

"I don't know who he represents. He doesn't represent me," Gregoire said. "I don't think he represents a million and a half Washingtonians that will be helped by this. I don't think he represents small business that will be helped by this. I don't think he represents Medicare people who will be helped by this."

In a statement announcing his decision Monday, McKenna said he believes the health-care measure's requirement that everyone buy health insurance is unconstitutional.

"I believe this new federal health care measure unconstitutionally imposes new requirements on our state and on its citizens. This unprecedented federal mandate, requiring all Washingtonians to purchase health insurance, violates the Commerce Clause and the 10th amendment of the US Constitution."

"I'm concerned that the measure unconstitutionally requires all Washingtonians to purchase health insurance and places an extraordinary burden on our state budget by requiring Washington to expand its Medicaid eligibility standards in violation of our state's rights guaranteed under the10th amendment."

McKenna joins several other Republican attorneys general, who talked about the legal challenge in a conference call last night, according to a statement from South Carolina Attorney General Henry McMaster.

In addition to South Carolina and Washington, the attorneys general of Florida, Texas, Nebraska, Utah, North Dakota, South Dakota, Pennsylvania, Oklahoma and Alabama would join the effort, according to McMaster's statement.

"We will take our case to the United States Supreme Court if necessary," McMaster said.

Gregoire said she spoke with McKenna Monday morning after hearing he would be joining the lawsuit along with other Republican attorneys general.

Gregoire said she told him to "get ready to represent me" because she intends to file a legal brief opposing McKenna's action.

Although McKenna is independently elected, Gregoire said she believes he had a "duty" to consult with other top state officials before agreeing to sue the U.S. government.

McKenna first threatened a lawsuit over the legislation back in December.