Berlin - German Chancellor Angela Merkel's government suffered a shock setback Friday, with the upper chamber of parliament refusing to pass a bill that would authorize police to use computer viruses to hunt terrorists.

The legislation had already been passed by the Bundestag lower chamber, where Merkel's grand coalition has a big majority, and had been expected to sail through the upper chamber which represents 16 state governments.

Most of the states are controlled by Merkel's Christian Democratic Union (CDU) or their allies, and her control of the Bundesrat has been fundamental to her authority since she became chancellor in 2005.

But several states, where the CDU rules in coalition with smaller parties, abstained Friday when the bill was submitted for a vote. A second resolution, to refer the bill back to a committee of both chambers, also failed.

The bill reforms the federal police and includes powers to break into personal computers during preventive inquiries into terrorism and other serious crime. Civil liberties groups objected.

The police have been studying whether they could either enter premises to plant monitoring devices in computers or send viruses to the computers via the internet so that investigators could covertly read the hard disks.

Critics also claimed the bill would impinge on the vow of silence by journalists, lawyers and doctors. (dpa)