Two men were stabbed at the weekend, with one dead and another in hospital in a serious condition.
The latest attack happened in Ipswich and the victim, in his 20s, was taken to hospital, where his condition is described as serious but stable.
Suffolk Police said they are not linking the attack with the fatal stabbing of 17-year-old Tavis Spencer-Aitkens in the town last weekend.
Police were called to an address in Pauline Street, Ipswich, by the ambulance service in the early hours of Monday.
Four people, described as "black men who were wearing face coverings", reportedly entered the address shortly before 1am and attacked the victim by stabbing him with a knife, police said.
The men were reported to have fled down a back alley towards Station Street.
"There is currently a police scene in place at the address," a Suffolk Police spokesman said.
"At this very early stage of the investigation, officers believe that this was a targeted attack, but are not linking this incident with the murder of Tavis Spencer-Aitkens that took place last weekend.
"Police are keeping an open mind as they investigate the full circumstances of what has taken place."
Another man, 35-year-old Edmond Januzi, was stabbed in London on Saturday. Januzi was an Albanian national thought to have lived locally.
The attack happened in Green Lanes, Haringey, and Januzi was pronounced dead at the scene.
It marks the 74th murder in London this year, and Januzi's next-of-kin have been informed.
Home Secretary Sajid Javid and London Mayor Sadiq Khan will meet today to discuss how to tackle the surge in crime.
Detective Inspector Garry Moncrieff of HMCC said: "It would appear that an altercation occurred between two groups of males in the Ducketts Common area at around 9.45pm on Saturday evening.
"Edmond was stabbed during that altercation.
"This was a busy area, very near to Turnpike Lane tube station. There will be people who saw or heard something suspicious that could help us find whoever killed Edmond.
"I am appealing for any witnesses or anyone with information to call the incident room at Hendon and share their accounts and that information with police."
Any witnesses - or anyone with information that may assist the investigation - are urged to call police on 101 quoting reference 7472jun09.