Swedish Foreign Minister Anna Lindh has died in hospital from stab wounds inflicted while she was shopping in a Stockholm department store.
Lindh was one of Sweden's most popular politicians
Lindh, who suffered injuries to the chest, stomach and arms in the attack on Wednesday, spent most of the night in surgery as doctors tried unsuccessfully to save her life.
Her attacker remains at large and the motive for the killing is not known.
Anna Lindh was a leading campaigner for Sweden to join the euro in a referendum which, it has been decided, will go ahead as planned on Sunday.
Her death has shocked a nation that has long prided itself on the accessibility of its politicians. Like many officials,
Lindh did not use a bodyguard.
An active politician since her early twenties, her meteoric rise in the ruling Social Democratic Party, and her solid reputation led her to be widely tipped as a possible successor to Prime Minister Goran Persson.
Mr Persson described her death as "beyond belief" and said it had hurt Sweden's open and democratic society.
"Sweden has lost one of its most important representatives," he added. "It feels unreal, it is difficult to truly understand."
Lindh died after undergoing surgery for more than 10 hours at Karolinska Hospital. She had severe internal bleeding, with injuries to her liver and stomach.
Her killing stirred memories of the murder of Swedish Prime Minister Olof Palme, who was shot in the back as he walked home from the cinema with his son and his wife in 1986.
His murder has never been properly explained.
Police hunt suspect
In the wake of the stabbing, both the Yes and No campaigns in the Swedish euro referendum suspended their activities.
The government considered postponing the vote, but Mr Persson said on Thursday it would go ahead as planned.
Polls have consistently indicated that the No-side will win, though correspondents say Ms Lindh's death could now boost the Yes vote.
Lindh had been shopping unaccompanied by bodyguards when the attack took place at about 1600 local time (1400GMT) on Wednesday.
She was carried from the Nordiska Kompaniet store on a stretcher.
"She lay on the floor and it looked as if a tall man, wearing a peaked cap, was hitting her," eyewitness Hanna Sundberg said.
"But when he ran away, he threw away a knife."
Police are searching for a man wearing a camouflage jacket who fled from the store.
Security has been tightened around government buildings, but police said there was as yet no evidence of a political motive.
Lindh, 46, had been foreign minister since 1998. She was married with two children.
At times outspoken, she argued forcefully in EU forums on human rights.
She called President George W Bush a "lone ranger" for going to war in Iraq and she criticised Italy's current EU presidency, saying that Prime Minister Silvio Berlusconi did not enjoy wide support.
Christian Democratic leader Alf Svensson said he was "at a loss for words to describe the sorrow and anger" he felt at the news of Lindh's death.