The Federal Trade Commission announced Wednesday that it has sued Intel Corp., the world's largest chip maker, alleging it has “used its dominant market position for a decade to stifle competition and strengthen its monopoly.”

The commission says Intel has acted in a way in order to block rivals from competing with the company in the semiconductor marketplace. The chipmaker allegedly threatened the biggest computer companies to coerce them not to install rivals' microchips in their PCs.

In a statement, the FTC said Intel “put the brakes on superior competitive products that threatened” its microchip market share.

Intel has engaged in a deliberate campaign to hamstring competitive threats to its monopoly, said Richard A. Feinstein, director of the agency’s Bureau of Competition.

It’s been running roughshod over the principles of fair play and the laws protecting competition on the merits.

The FTC contends that the company’s anti-competitive tactics … succeeded in maintaining the Intel monopoly at the expense of consumers, who have been denied access to potentially superior, non-Intel CPU chips and lower prices.

The commission says Intel is engaging in similar tactics in graphics processors, “smothering potential competition” from companies like Nvidia.

This is not the first time that Intel has been in hot water. Last month, the chip maker agreed to pay $1.25 billion to settle long-running disputes with A.M.D. That settlement covered both antitrust and patent claims.

Intel is down 31 cents or 1.6 percent on the Nasdaq to $19.49 in morning trading.