Three people are believed to have died after an incident at a hotel in Glasgow city centre.
It is thought that two people were fatally stabbed before the attacker was shot dead by armed police.
Six people are being treated in hospital for their injuries, including a police officer who was said to be “critical but stable”.
Police Scotland said the situation was “contained” and there was no danger to the general public.
Armed officers remain at the scene outside the Park Inn in West George Street.
First Minister Nicola Sturgeon said reports of the incident were “truly dreadful” and she was being “updated as the situation becomes clearer”.
She added: “My thoughts are with everyone involved.”
UK Prime Minister Boris Johnson said he was “deeply saddened by the terrible incident in Glasgow”.
A senior Whitehall source has told the BBC the motive for the stabbings is still being investigated and it is “too early” to say if it is related to terrorism.
Police Scotland Assistant Chief Constable Steve Johnson urged people to avoid the area.
He said police were not looking for anyone else in relation to the incident.
“The individual who was shot by armed police has died.
“Six other people are in hospital for treatment to their injuries including a police officer, who is in a critical but stable condition,” he said.
It is understood that the Park Inn Hotel is currently being used to house asylum seekers.
One witness, who gave his name as John, said he came down from the third floor of the hotel to see the reception covered in blood.
He told the PA news agency that he initially saw one person who had been stabbed.
“I went down to the entrance and shouted at him and told him to stay calm and I will call for help,” he said.
He then saw another man, who was “fighting for his life”.
Another witness, Craig Milroy, saw the aftermath of the incident from an office building nearby and said he had seen four people taken away in ambulances.
He said: “I saw a man lying on the ground, of African descent, with no shoes on. He was on the ground with someone holding his side – I don’t know if it was a bullet wound, a stab wound, or what it was.”
Mr Milroy said the man was one of the four taken away by medics and believed him to be a victim of an attack.
He added: “After that we saw commotion, ambulances further up and we saw armed police all running into the hotel next to the Society Room.
“We were still standing outside, after that the police all came down, the riot police and triage team told us to go back in and lock the door.”
