Chris Benedict, 24, was detained in the biblical city of Bethlehem, where he had served as a Brigades gunman in the uprising for an independent state in the West Bank and Gaza Strip, Palestinian security sources said.

They said Benedict was the only known Christian member of the Brigades, an offshoot of Palestinian leader Yasser Arafat's Fatah movement whose name refers to a major Muslim shrine in Jerusalem.

Most of the 3.6 million Palestinians in the occupied territories are Muslim. Only about 60,000 are Christian. Western names are not uncommon among Arab Christians.

An Israeli army spokeswoman described Benedict as a "senior terrorist" suspected of involvement in ambushes of Israeli vehicles and helping plan two suicide bombings in which 13 Israelis were killed.

The spokeswoman said another four suspected militants had been arrested on Wednesday in West Bank sweeps which have become almost daily events since Israel reoccupied much of the territory last June following waves of Palestinian attacks.