A lawsuit filed on Tuesday accuses Ethiopia of infecting a US man's computer with "spyware" as part of a campaign to gather intelligence about those critical of the government.

"We have clear evidence of a foreign government secretly infiltrating an American's computer in America, listening to his calls and obtaining access to a wide swath of his private life," said attorney Nate Cardozo of Internet rights group Electronic Freedom Foundation.

"The current Ethiopian government has a well-documented history of human rights violations against anyone it sees as political opponents."

The computer of a US citizen living in the state of Maryland was targeted with malicious software that monitored use and snooped on calls made using Internet telephone service Skype, the suit charges.

The malware was slipped onto his machine when he opened an emailed document file booby-trapped with a program called FinSpy, according to the EFF.

Analysis of the computer showed that recordings of Skype calls and other data was sent to a server in Ethiopia controlled by the government there, the EFF charged.

The court was asked to let the plaintiff be identified by the pseudonym "Mr. Kidane" to protect members of his family here and abroad from reprisal.

"The problem of governments violating the privacy of their political opponents through digital surveillance is not isolated -- it's already big and growing bigger," said EFF legal director Cindy Cohn.

The complaint filed in federal district court in the US capital of Washington calls for a jury trial along with damages to be paid for violations of US law.