JERUSALEM • A bomb blast which ripped through a bus in Jerusalem and sparked a fire wounded at least 21 people, in an apparent escalation of a wave of violence.
Police said a bomb had exploded on one bus in a relatively isolated area of Jerusalem on Monday, with the flames spreading to another one, as well as a car. Israeli domestic security agency Shin Bet referred to the explosion as a "terror attack".
The bombing was expected to lead to a sharp increase in security ahead of Jewish Passover celebrations beginning on Friday night.
If confirmed as a Palestinian bombing, it would both reverse a decline in a wave of violence that erupted in October and mark an escalation, with most of the attacks having been stabbings.
"A professional examination of police sappers has proven that a bomb exploded on the back part of the bus, resulting in the wounding of passengers and the burning of the bus," a police statement said.
Many Israelis reacted with alarm on social media, The New York Times reported, saying they were reminded of the second Palestinian uprising, which erupted in 2000 when suicide bombers blew up buses in Jerusalem and cities around Israel, killing scores of people.
Israeli Prime Minister Benjamin Netanyahu said "we'll find whoever prepared this explosive device".
"We'll reach the dispatchers and those behind them. We'll settle the score with these terrorists. We're in an ongoing struggle against terror, knife terror, shooting terror, bombs, rockets and tunnel terror."
The Palestinian Islamist group Hamas, which rules the Israeli-blockaded Gaza Strip, welcomed the attack as "a natural response to Zionist crimes", but there was no claim of responsibility for the bombing.
The blast took place in an area without any major buildings or homes and which is not heavily used by pedestrians. The bus was on Moshe Baram Street, close to the so-called Green Line dividing mainly Jewish west Jerusalem from mainly Palestinian east Jerusalem.
Singapore condemned the bus bombing. "We are confident that the authorities will bring those responsible for this act of terror to justice swiftly," a Ministry of Foreign Affairs spokesman said in a statement.