Prime Minister Benjamin Netanyahu prepared Israel for a long drawn-out operation to find three missing teenagers as troops expanded the search into a crackdown on the Islamist group accused of abducting them and arrested dozens of its officials.

Israel says members of Hamas, which signed a unity deal with Palestinian President Mahmoud Abbas in April, kidnapped the three seminary students, who disappeared on Thursday after leaving a Jewish settlement in the occupied West Bank.

Netanyahu said in televised remarks from a military base that the effort to retrieve the youths was a "complicated operation," and added "we must be prepared for the possibility it could take time".

He also said Israel had arrested more than 100 Hamas members in the West Bank and was "carrying out other actions".

...