The three disappeared late Thursday in the West Bank, reportedly while hitchhiking. An official has said one is a US citizen.
Israeli troops have scoured the southern West Bank, near the Palestinian city of Hebron, and have arrested more than a dozen Palestinians.
If confirmed that the three teenagers, aged 16 and 19, were seized by Palestinian gunmen, it would be the biggest kidnapping by such militant groups in recent memory in the West Bank.
Israeli Defence Minister Moshe Yaalon said today that Israel has thwarted dozens of kidnapping attempts by militants, including 14 so far this year.
"It appears this event slipped under our radar, but we will not rest until we free the youths and put our hands on the terrorists who are responsible for this operation," Yaalon said.
He added: "As long as we don't know otherwise, our working assumption is that they are alive."
Today, local media published the names of the teens and their home communities, two West Bank settlements and one in Israel.
Israel's government held Palestinian President Mahmoud Abbas responsible for the fate of the teens.
"The current crisis is a direct result of the decision by Palestinian President Mahmoud Abbas to force a political alliance with these Hamas terrorists," said Mark Regev, a government spokesman.
Hamas, branded a terror group by the West for its attacks aimed at civilians, has been involved in kidnappings of Israeli soldiers in the past.
