Police in Norway, Finland, Sweden and Denmark say they questioned some 350 people suspected of purchasing child pornography on the internet.

Large numbers of computers, CDs and videos were seized, but it is not yet clear how many people will be charged.

The raids were a culmination of a year-long investigation, police said.

The co-ordinated raids started at 0600 local time (0400 GMT) in each of the four countries.

They targeted "people suspected of having taken possession of material documenting sexual abuse of children," Norway's deputy police commissioner Siri Frigaard was quoted as saying by the Associated Press news agency.

In Norway, officials said they questioned 153 suspects after nearly 200 raids across the nation, while Swedish police said more than 100 people were being interviewed.

In Denmark, at least 40 people were briefly detained for questioning after their homes were raided.

Credit cards

Finnish authorities said they were investigating 37 suspected cases.

"We made a great number of seizures of computers, CDs, video tapes and the like, but what the material contains we don't know yet," Swedish police spokesman Per-Olof Forslund said.

"It will take quite some time to examine it all," the spokesman added.

Most of those detained appear to have been identified by through credit cards which had been used to buy child pornography over the internet, the local media said.