Police arrested a man Tuesday after three people were found dead and a van tried to mow down three others in the central English city of Nottingham in incidents authorities believe are linked.
Nottingham's centre was cordoned off, with a heavy police presence, including some armed officers following the events that left residents shaken.
A 31-year-old man has been arrested on suspicion of murder, police said.
Prime Minister Rishi Sunak thanked emergency services who had dealt with the "shocking incident" in the city, which is home to more than 320,000 people.
"My thoughts are with those injured, and the family and loved ones of those who have lost their lives," he added.
Police were called just after 4:00 am (0300 GMT) after two people were found dead in Ilkeston Road, which runs west out of the city centre between the city's two university campuses.
Residents reported hearing screams and seeing a young man and woman being stabbed, before the attacker -- said by one witness to be a "black guy dressed all in black with a hood and rucksack" -- walked off calmly.
The body of a man was also found on Magdala Road, about two miles (3.2 kilometres) away, police said.
The three people hit by the van, in Milton Street, in the city centre, were being treated in hospital, the force added in a statement.
A white Vauxhall van with a shattered windscreen was cordoned off a mile away outside a convenience store, an AFP photographer said.
A black rucksack was seen on the road under the vehicle's open passenger-side door.
- Sirens -
Witness Lynn Haggitt said she saw a van hit two people at around 5:30 am near the city's Theatre Royal after the vehicle pulled up beside her on her way to work.
"He looked in his mirror, saw a police car behind him, he then quickened up, there were two people... he went straight into these two people," she told BBC news.
Another man, Glen Gretton, said he was woken up at around 5:00 am by the sound of police cars passing his home.
"I heard a police car go past. It was driving extremely quickly, followed by another one, another one," the 46-year-old delivery driver said.
"They just kept coming so I knew something quite major... was happening somewhere around the city centre," he said.
"This is an horrific and tragic incident which has claimed the lives of three people," said Nottinghamshire Police Chief Constable Kate Meynell.
"We believe these three incidents are all linked and we have a man in custody," she added.
The city's tram network was suspended while the investigation took place.
Home Secretary Suella Braverman said she was "shocked and saddened" by the deaths.
The city's three members of parliament -- Nadia Whittome, Lilian Greenwood and Alex Norris -- said they were "shaken" by the events and expressed their condolences to the families of the dead and injured.
"Our city has been devastated by the deaths of three people this morning. Nottingham is a beautiful city, home to brilliant people from all backgrounds.
"We are shaken by today's events but will meet them collectively as a community and heal together," they said in a joint statement on Twitter.
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