A blast caused by a bomb on a bus in Jerusalem has injured at least 21 people, two seriously, in the first attack of its kind to take place in the Israeli capital in several years.
"Police bomb disposal experts confirm explosive devise went off on bus that caused 21 injuries," tweeted Israel Police foreign press spokesperson Mickey Rosenfeld. Israel's internal security service Shin Bet characterized the blast, which occurred around rush hour, as a terror attack.
It is not yet clear whether the explosion was caused by a suicide bomber or by a planted device. Police said an initial investigation determined that it occurred toward the back of a crowded bus at the corner of Bar'am Road and Hebron Road in Talpiot, an industrial zone just south of the city center, causing two buses and a private vehicle to catch fire.
Attacks on Israeli buses by suicide bombers — many of them claimed by Hamas, the Palestinian militant group that now administers the Gaza Strip — were a hallmark of the Palestinian uprising between 2000 and 2005 but have been rare since, with the last one carried out in 2012 in Tel Aviv.
Confusion surrounded the explosion at first, with the police initially reporting preliminary findings suggesting that the blast was a terror attack and then clarifying that authorities were investigating all possibilities before finally confirming that it was a bomb attack.
In a public address following the blast, Israeli Prime Minister Benjamin Netanyahu sympathized with the injured civilians and vowed to avenge the attack.
"We'll get to those who prepared this bomb," he said, "and settle the score with the terrorists."
According to local media, among the wounded who were evacuated to Shaare Tzedek Medical Center were a 30-year-old man in serious condition, with wounds to his lower body; a 50-year-old woman, a 25-year-old man, and a 16-year-old boy in moderate condition; and a 48-year-old woman, a 45-year-old man, a 12-year-old boy, and a 10-year-old boy with light wounds.
Monday's bus bombing marks a significant uptick in a six-month spate of violence in which 28 Israelis have been killed by Palestinians in a series of stabbing, shooting, and vehicle attacks. On the other side, 188 Palestinians have died, including 144 that Israeli security forces say were killed while carrying out attacks. The remaining 44 were killed during clashes.
Israel has blamed the wave of violence on social media for allowing Palestinian users to post and share how-to videos on stabbing attacks, as well as violent memes and videos glorifying killers as martyrs.
Tensions have also flared in recent months over Al-Aqsa Mosque, a contested holy site known to Jews as Temple Mount. A growing number of visitors are expected at the site as the Jewish holiday of Passover approaches, causing some Palestinian religious leaders to warn that the sanctity of the site is at risk.
No group has yet claimed responsibility for Monday's attack, but Hamas tweeted that it "welcomed" the bus blast and considered it "a natural response to Israeli crimes, in particular the execution of civilians and the desecration of Al-Aqsa Mosque."
The Arabic hashtag attached to the tweet translates as, "roof of the bus goes flying," an apparent reference to the title of a pop song encouraging Palestinians to blow up "Zionist buses" in Israel released earlier this year.
Islamic Jihad and Popular Front for the Liberation of Palestine have also praised the attack.
Follow Harriet Salem on Twitter: @HarrietSalem