Prime Minister Benjamin Netanyahu again blamed the Palestinian Authority for the last disappearance of the teens, one of them a US citizen. Palestinian officials say they are assisting Israeli forces, who poured over surveillance footage today and arrested more than a dozen Palestinians.
Netanyahu said an "intensive operation" was underway to prevent the teens from being taken to the Gaza Strip or elsewhere.
"Our children were kidnapped by a terror group," he said. "There is no doubt about that."
Their kidnapping is the biggest abduction by militant groups in recent memory in the West Bank.
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Israeli-Palestinian tensions already were strained at the time of Thursday's kidnapping, in part because of the recent formation of a Palestinian unity government that has the backing of the Islamic militant group Hamas.
Israeli Defense Minister Moshe Yaalon said today that Israel has thwarted more than a dozen kidnapping attempts by Palestinian militants so far this year.
"As long as we don't know otherwise, our working assumption is that they are alive," he said.
Hamas, branded a terror group by the West for its attacks aimed at civilians, has been involved in kidnappings of Israelis in the past. The group routinely claims responsibility if involved in an attack, but has not claimed taking the teens.
Palestinian officials also rejected Israel's attempts to blame Abbas, noting that Israel retains overall security control in the West Bank.