Violent knife offences reached record levels in Suffolk and continued to rise in Essex, according to the latest crime statistics.
Overall crime rose 5% in Suffolk and 17% in Essex in the year ending September 2019.
Serious crime involving knives - including GBH, robbery and threats to kill - reached record levels in England and Wales since comparable Office for National Statistics data began in 2010/11.
In Suffolk, the number reached 285 - up 44% in a year and completing a 59% rise since 10/11.
Police said it amounted to one additional crime per week, but insisted they took the rise seriously and were "relentless" in keeping the community safe.
Essex recorded 865 serious crimes involving knives - up 22% in a year and 61% since 10/11 - but lower than the 992 seen in 16/17.
The rate of serious crimes involving knives was just 3% in Suffolk and 4% Essex - but reached 16% in Suffolk and 19% in Essex for robberies.
Meanwhile, violence, harassment, robbery, drugs and sex offences rose across both counties - where violence against the person accounted for about a third of all crime.
But there were sustained falls in burglary (down 12% in Suffolk and 8% in Essex) and theft from the person (down 16%).
Suffolk's Temporary Deputy Chief Constable, Simon Megicks said police were concerned about the rise in knife crime, but highlighted that the number amounted to one additional offence a week.
"I'm not seeking to minimise it," he added.
"Our focus is on that serious end of criminality. We have a youth gang prevention unit targeting younger people who carry knives.
"Our use of stop and search is up 50% in the same reporting period. We have a dramatically high return rate and knife crime arrests have increased 10%.
"This is serious, and we're not complacent. It's not for us to give this up as a societal issue.
"It's plainly stupid to carry a knife, and you're at greater risk of injury, but that doesn't resonate with people who carry them.
"Our key message is don't carry a knife, because we'll get you.
"We have to put this into perspective. We don't want people to think it's out of control, because it isn't.
"We are pushing our organisation to record everything, and we're more proactive than we've ever been, so that has an impact on figures. If you dedicate focus on looking for crime, you're more likely to find it."
Mr Megicks said reductions elsewhere showed positive work was being done to ensure the population felt safe in their own homes.
He said officers were fulfilling the expectations of society and police to take positive action against domestic violence.
He welcomed the arrival of the government's promised additional officers, which will follow local investment in teams set up to target organised crime, and influential in rounding up members of the Neno drug gang sentenced to more than 72 years in prison last month.
"This is about keeping the community safe, and we will be relentless in doing that," he added.
A spokesman for Essex Police said: "Today's crime figures highlight that Essex remains a safe place to live, work and study.
"Fewer people are victims of violence with injury offences, robbery, theft, and burglary than the national average.
In fact, we saw more than 1,000 fewer burglaries across Essex in the year to September 2019 than the year before. Anti-social behaviour has also fallen.
Crime is going up across the country, and Essex is no different, which is why we continue to invest to better support victims, protect the vulnerable, tackle violence, and increase visibility.
"As well as introducing new Town Centre Teams and expanding our Rural Engagement Team, we've secured millions of pounds in extra funding to tackle and prevent street violence and knife crime.
"Through proactive police work, such as the responsible and proportionate use of stop and search, we've also seen drugs offences and possession of weapons offences rise.
"This represents the hard work policing that takes place across the county every day to tackle drug dealers and get weapons off our streets.
"A record number of new officers passed out last year, and we're recruiting and training more. We are currently on track to having 3,218 officers protecting and serving the county by March 2020 and 3,353 by 2021.
"Yesterday (Wednesday) the government and Police and Crime Commissioner for Essex announced more investment in policing which will see the continued growth of officers.
"We've improved how accurately we record crime, and our data accuracy is now rated as 'outstanding' by the HMICFRS, and this has had an impact on the number of offences recorded.
"It means in some areas we've seen the number offences recorded increase more steeply than before and than other parts of the country.
"We've also improved our processes for identifying and recording crimes involving the use of knives or sharp instruments.
"By being able to record offences more accurately we get a better picture of the issues we need to tackle the most as well as providing a better service to victims."
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