Attorney General Richard Blumenthal, one of the most visible figures in the antitrust case against Microsoft, confirmed Tuesday he will not join a proposed settlement reached with half of the 18 states suing the software giant.

Blumenthal had said previously he was leaning against signing the agreement. He said Tuesday the deal "has too many gaps and ambiguities."

"The settlement reflects good progress, but not good enough," Blumentle the lawsuit. Nine other states, including Connecticut, indicated they would press forward with the case.

States agreeing to the settlement are Illinois, Kentucky, Louisiana, Maryland, Michigan, New York, North Carolina, Ohio and Wisconsin.

Aside from Connecticut, states that have definitely rejected the agreement are California, Iowa, Kansas, Minnesota, Massachusetts, Utah and West Virginia.

Florida and the District of Columbia are leaning against the settlement.

Blumenthal said he feels the settlement needs a stronger enforcement mechanism and tighter safeguards against retaliation, among other concerns.

"Our goal has always been to make sure that Microsoft's monopolistic misconduct is prevented from recurring and competition is restored, so that consumers benefit from more innovation and better prices and quality," he said.

Microsoft spokesman Jim Desler said, "We believe the settlement is a fair and reasonable compromise. We were hopeful Attorney General Blumenthal would agree with us."

He said the company remained willing to clarify any questions but would not make any further concessions.

Shares of Microsoft were off $1.92, or 3 percent, to $63.22 in trading on the Nasdaq Stock Market.

The proposed settlement would require Microsoft to give independent monitors full access to its books and plans for the next five years, and to provide information to help rivals make their products compatible with Windows. It would also give computer manufacturers more latitude to remove Windows features and replace them with competing products.