BRUSSELS/ATHENS (REUTERS) - Belgian prosecutors are seeking the extradition of a person arrested in Greece over a possible link with a foiled Islamist plot to attack Belgian police, officials said on Sunday.

Greek and Belgian officials had said earlier there was no connection between the arrest of more than half a dozen people on Saturday in Athens and events last week in Belgium, where police carried out deadly raids.

"Further analysis of the elements of our investigation gave us enough reasons to ask for the extradition of one of the persons that were arrested yesterday by the Greek authorities," the Belgian federal prosecutors' office said in a statement.

In Greece, a police official said he could not confirm the extradition request. "We have sent material to the Belgian authorities from the people that we detained," he said, referring to DNA samples.

On Thursday, police killed two gunmen during raids in the east Belgian town of Verviers.

Police subsequently carried out a series of arrests throughout the country and Eric Van Der Sypt, a spokesman for the prosecutors' office, said on Belgian television further searches had taken place in the Brussels area on Sunday.

He also said prosecutors were looking for other people in Greece and were working with the Greek authorities.

Belgian state broadcasters have said the authorities were seeking a Brussels man of Moroccan origin who had been hiding in Greece, but the prosecutors have refused to release any names, arguing it would hinder their investigations.

To try to guard against any further attacks, Belgium is deploying up to 300 troops to protect possible targets, including U.S. and Israeli diplomatic missions and Jewish schools and sites.