Seven people were injured, two of them critically, after a shooting attack on a bus in Jerusalem's Old City, Israeli police and medics said early on Sunday.
Police detained the suspected shooter, who apparently surrendered to security forces during a pre-dawn raid on Sunday. A pregnant woman and several US citizens were among the injured.
"The terrorist is in our hands," police spokesman Kan Eli Levy told Israeli public radio hours after the bloody attack not far from the Western Wall, the holiest prayer site for Jews.
The US embassy confirmed that several American citizens were among the wounded, declaring that "we are shocked and saddened by the terrorist attack", but gave no further details on the victims, citing privacy concerns.
Israel's emergency medical services, the Magen David Adom, called the incident a "terror attack in the Old City".
"We were on the scene very quickly," paramedics said.
"On Ma'ale Hashalom Street we saw a passenger bus standing in the middle of the road. Bystanders called us to treat two males around 30 years old who were on the bus with gunshot wounds."
Speaking to The Associated Press after the attack, the director of the Trauma Unit at Shaare Zedek Medical Centre, Alon Schwarz said six of the injured were undergoing treatment.
"Two wounded in a serious condition - a pregnant woman in her 30s with an abdominal injury, still in the operating room, a very complex injury. And a man in his 60s with an injury on the neck and head, also a gunshot wound, and is now in the intensive care unit, ventilated and sedated, and we are currently deciding whether to operate on him as well."
Four others suffered from more moderate injuries, he said.
Bus driver Daniel Kanievsky said the attack occurred near King David's Tomb.
"I was coming from the Western Wall. The bus was full of passengers. I stopped at the station of the Tomb of David. At this moment starts the shootings. Two people outside I see falling, two inside were bleeding. Everybody panicked," he said.
Defence Minister Benny Gantz called the attack "serious" and said security forces will capture the assailants.
"Praying together with all the citizens of Israel for the healing of the wounded, he said.
Prime Minister Yair Lapid made similar comments on Sunday.
"The security forces, the Shin Bet, the IDF, and the police are working to get the despicable terrorist and will not stop until he is caught," he wrote on Twitter.
"Let all those who seek our harm know that they will pay a price for any harm to civilians," he added.
The Palestinian militant group Hamas, which controls the Gaza Strip, hailed a "heroic operation" without claiming responsibility for the attack.
"Our people will continue to resist and fight the occupier by all means," it said in a statement.
The shooting came a week after the end of a three-day conflict between Israel and Islamic Jihad militants in the densely populated Palestinian coastal enclave of Gaza.
At least 49 Palestinians, including Islamic Jihad fighters and a number of children, died in the violence which ended last Sunday after Egypt negotiated a truce.
Since March, 19 people ― mostly Israeli civilians inside Israel — have been killed in attacks. Three Israeli Arab attackers were also killed.
In the aftermath of those attacks, Israeli security forces stepped up raids in the occupied West Bank.
More than 50 Palestinians have been killed, including fighters and civilians, in operations and incidents in the West Bank since then.