Austrian police have arrested 13 people suspected of recruiting fighters for radical Islamic groups in the Middle East.

The state prosecutor's office says they were arrested early Friday in a sweep covering homes and mosques in Vienna, the southern city of Graz and Upper Austria province.

It says the arrests follow two years of observation of the suspects that included listening in on their telephone calls.

A statement says searches yielded "terroristic propaganda material," an unspecified amount of cash and stored computer data.

The suspects were not identified, in line with Austrian privacy laws.

About 500 police officers participated in the searches and arrests.

The Interior Ministry says that about 150 people have joined radical Middle East groups from Austria.