A 16-year-old boy has been killed and 14 other people have been wounded in two suspected bomb attacks at bus stops in Jerusalem, Israeli police say.
The explosions happened at two busy areas on the outskirts of the city as people were heading to work.
Israeli media said the teenager who died was an Israeli-Canadian religious student named Aryeh Shtsupak.
Israel's internal security minister said at one scene that this was "an attack we haven't seen in a long time".
The atmosphere in the city feels volatile in a year of intensifying violence: Palestinian gun and knife attacks have targeted Israelis, and Israeli military raids have killed Palestinian gunmen and civilians in the occupied West Bank.
A return to the use of explosives in Jerusalem makes it one of the most significant attacks of its kind in years.
No group has so far said it was behind the blasts. However, the Palestinian militant groups Hamas and Islamic Jihad both praised the perpetrators of what they referred to as the "operation".
The first explosion happened in Givat Shaul, close to the main entrance to Jerusalem, just after 07:00 (05:00 GMT) on Wednesday.
Israeli medics said the blast wounded 12 people, including the teenage boy who died later at the Shaare Zedek Medical Center.
About 30 minutes later, there was a second blast in Ramot Junction, another entrance to the city. It left three people with minor injuries.
At the scene of the first explosion, the pavement was scattered with debris. Masked Israeli security forces sealed off the site, while the pieces of a badly damaged bicycle were put into forensics bags.
One man from a Jewish ultra-Orthodox neighbourhood opposite told the BBC that he was woken as his building shook. Many of those waiting for buses were apparently from the community.
A small protest was also taking place with a sign held by young Israeli men calling for "revenge".
The head of the Israeli police's operations division, Deputy Commissioner Sigal Bar Zvi, said the bombs were made with "high quality" explosives and that they were placed in a bush and behind a wall at the bus stops.
Given the nature of the attacks, she added, investigators suspect they were masterminded by an organised cell.
Israeli media cited security sources as saying that both devices contained nails and were likely to have been detonated remotely.
Earlier, Police Commissioner Kobi Shabtai said the attacks were unlike any seen in recent times.
Officers were scanning "all possibly hazardous areas, whether at bus stations, buses or crowded areas" for more bombs and were "making an effort to get our hands on whoever committed this terror attack".
Bombings were a feature of the second Palestinian intifada, or uprising, which began two decades ago. But Jerusalem has not seen one since 2016.
Outgoing Prime Minister Yair Lapid convened a special meeting with the country's security chiefs.
In an address at a ceremony in Jerusalem, Israeli President Isaac Herzog said: "This terror attack will not weaken us, will not make us doubt our belief in our ways, or in our right to a peaceful and safe life in Israel, including in our eternal capital of Jerusalem."
The attacks come as Prime Minister-designate Benjamin Netanyahu and his Likud party continue negotiations to form a new coalition government with allied far-right and religious parties. They won a majority in parliament in an election that centred on security.
"We still have a fight with cruel terror, which raise its head again," Mr Netanyahu warned as he visited survivors of the attacks in hospital. "We will do anything to bring back the security for the citizens of all Israel as soon as possible."
Ultra-nationalist Otzma Yehudit (Jewish Power) party leader Itamar Ben-Gvir, who is set to become Mr Netanyahu's internal security minister and oversee the police force, visited the scene of the first explosion and declared that Israel had to take action to deter Palestinian attacks.
"Even if it's in the West Bank, lay siege to them and go from house to house in search of guns and restore our deterrence power," he said.
Canada's ambassador to Israel, Lisa Stadelbauer, said she was "heartbroken to confirm that a young Canadian lost his life in this morning's reprehensible terror attack in Jerusalem".
"Our sincere condolences to his family and friends, and to others wounded in this attack. Canada continues to condemn all forms of terror."
The US ambassador to Israel, Tom Nides, tweeted that an 18-year-old Israeli-American named Naomi Pilichowski was among those wounded in what he called the "heinous terrorist attack". Her father, the educator and author Rabbi Uri Pilichowski, said she had suffered a small cut.
White House spokeswoman Karine Jean-Pierre said the US condemned "unequivocally the acts of terror" in Jerusalem and that it had "offered all appropriate assistance to the government of Israel as it investigates the attack and works to being the perpetrators to justice".