Israel holds the Palestinian Authority responsible for the safe return of three teenagers kidnapped in the West Bank by a “terror organisation”, Prime Minister Benjamin Netanyahu says.

“Our young people have been kidnapped by a terror organisation … there is no doubt about that,” Mr Netanyahu said as a massive manhunt for the three youngsters entered its third night.

The teenagers, one of whom also holds a US passport, are believed to have been snatched on Thursday night between Bethlehem and Hebron, reportedly while hitchhiking. They were studying at two Jewish seminaries in settlements in the southern West Bank.

Their disappearance has prompted a huge search by the army and border police.

Mr Netanyahu said he placed responsibility for their safe return on the shoulders of Palestinian president Mahmud Abbas and his Palestinian Authority.

The Israeli leader demanded “the Palestinian Authority, headed by Abu Mazen (Abbas) – from whose territory the kidnappers came – do whatever necessary to help the hostages get home safely. That is the Palestinian Authority’s responsibility.”

The suspected abductions occurred 10 days after a new Palestinian unity government was sworn in, pieced together in agreement with the Islamist Hamas movement, in a development roundly denounced by Israel.

Israel has vowed to boycott all contact with the new government, whose emergence has ended seven years of divided rule between the West Bank and Gaza, with Mr Netanyahu insisting Mr Abbas be held responsible for all acts of violence emanating from anywhere in the Palestinian territories.

“We see Abu Mazen and the Palestinian Authority as responsible for every attack on Israel emanating from their territory, whether it is from Judaea and Samaria, or from the Gaza Strip”.

Earlier, a spokesman for the Palestinian security services rejected Israel’s accusations saying the incident occurred in an area under full Israeli civilian and security control.