Internet phone service provider SunRocket, which had as many as 200,000 customers nationwide, has ceased operations without warning.

The move by SunRocket, which offered service via Voice over Internet Protocol, or VoIP, was first reported Monday on The New York Times' Web site.

It was confirmed by Martin Pinchinson, a spokesman for Sherwood Partners LLC of Palo Alto, Calif., who said in an e-mail to The Associated Press that the financial consulting company was handling SunRocket's liquidation.

A message left at SunRocket's Vienna, Va., headquarters was not immediately returned. The privately held company's Web site was still up Monday night. But SunRocket's customer service line offered callers a brief recording: "We are no longer taking customer service or sales calls. Goodbye."

SunRocket laid off almost 200 employees at its Springfield, Mo., call center Monday, The Springfield News-Leader reported.

The company also laid off what its chief marketing officer called "a significant number" of employees July 3, five days after the firings of two top executives, Chief Technology Officer Mark Fedor and Chief Information Officer Robert Kramer. The company's chief financial officer, David Samuels, resigned July 2.

Some people identifying themselves as SunRocket customers on Internet discussion boards were complaining about outages Monday, while others said their service was working. The company has been known to have periodic outages in the past.

SunRocket, which started in 1994, was one of the first companies to offer Internet phone technology, and reported about 200,000 customers as of April, second only to Vonage Holdings Corp. as a stand-alone VoIP provider.