Updated

Nearly 80 percent of the 2,100 weapons recovered in New York City jails last year were shivs and shanks made from materials scrounged in the jailhouse, according to a new report that advocates say is at odds with the official view that smuggled razors are behind a recent surge in stabbings and slashings.

But the report released this week by the Board of Correction, the city jail oversight body, stopped short of linking the violence to a specific type of weapon, noting that a weapon is recovered in only about 20 percent of inmate-on-inmate stabbings. Guards conducted more than two million inmate searches last year amid tens of thousands of routine jailhouse searches.

It was clear on one point, however, saying the deteriorating condition of the Rikers Island jail complex, parts of which date to the 1930s, was itself a factor in the abundance of homemade weapons because it provides plenty of raw materials for them, including old radiator pipes and plastic light fixtures.

"The administration is committed to ensuring our facilities are in a state of good repair, which helps stem the tide of homemade weapons," Department of Correction spokeswoman Eve Kessler said in a statement.

Jail violence has continued to rise in recent years despite a steady decline in the overall jail population, which today hovers around 10,000 inmates. Stabbings and slashings have jumped from 25 in 2009 to 90 last year, with 44 such incidents already this year, 18 of which occurred in March, the statistics show.

The report comes ahead of a public meeting next month in which jail officials have said they'll ask the oversight board to change city rules to restrict inmate visits in an effort to stem the flow of contraband, including trafficked razor blades and medical scalpels that jail officials say have driven violence.

In fiscal year 2015, 284 visitors were arrested for attempting to smuggle in contraband, 29 for weapons and 171 for drugs, according to department of correction officials. Another 442 razor blades, scalpels, knives and other items were left in an amnesty box by visitors who at the last minute apparently decided not to smuggle them inside visitation houses, department officials said.

But inmate advocates and others say the report shows jail officials should focus less on restricting visitors and more on stemming the production of inmate-made weapons.

"This report calls into question the administration's focus on visitors as the source of weapons," said Jennifer Parish, an attorney at the Urban Justice Center's Mental Health Project.

Norman Seabrook, who heads the powerful Correction Officers' Benevolent Association, said there are too few guards in general inmate housing areas where the majority of violence takes place — and they're not properly trained to investigate stabbings and slashings and recover the weapons.

"If you take a toothbrush and file it down to a sharpened point, a brand new correction officer doesn't have experience with weaponry in a jail system to identify that and they can overlook that," he said.