HALHUL - Israel found the bodies of three missing teenagers on Monday, accusing Hamas of their murder and vowing to make the Islamist movement pay.

But a senior Hamas official warned Israel against any reprisals, saying it would open "the gates of hell".

The discovery of the three bodies in a field in the southern West Bank came 17 days after the youngsters disappeared, triggering a huge manhunt during which five Palestinians were killed and more than 400 arrested.

It also triggered a surge in rocket attacks against southern Israel by militants in the Gaza Strip, which triggered retaliatory Israeli air strikes almost nightly.

Israel has publicly blamed Hamas for the teenagers' abduction and staged a major crackdown on the Islamist movement's West Bank network.

But so far, the military has held back from attacking Hamas's power base in the Gaza Strip.

"This evening, we found three bodies and all the signs indicate that they are the bodies of our three kidnapped youngsters," Prime Minister Benjamin Netanyahu told ministers at the start of an emergency session of his security cabinet.

"They were kidnapped and murdered in cold blood by human animals.. Satan has not yet invented vengeance for the blood of small child," he said. "Hamas is responsible and Hamas will pay."

"If the occupiers carry out an escalation or a war, they will open the gates of hell on themselves," Hamas spokesman Sami Abu Zuhri told AFP. President Mahmud Abbas convened an emergency meeting of the Palestinian leadership to discuss the latest developments. Abbas has come under massive Israeli pressure to renounce the reconciliation agreement with Hamas.