A new report prepared for the United Nations Security Council warns that the militant group known as the Islamic State (Isis) possesses sufficient reserves of small arms, ammunition and vehicles to wage its war for Syria and Iraq for up to two years.

The size and breadth of the Isis arsenal provides the group with durable mobility, range and a limited defense against low-flying aircraft. Even if the US-led bombing campaign continues to destroy the group’s vehicles and heavier weapons, the UN report states, it “cannot mitigate the effect of the significant volume of light weapons” Isis possesses.

Those weapons “are sufficient to allow [Isis] to continue fighting at current levels for six months to two years”, the UN report finds, making Isis not only the world’s best-funded terrorist group but among its best armed.

Isis, along with its former rival turned occasional tactical ally the Nusra Front, are sufficiently armed to threaten the region “even without territory”, the report concludes.

The report, months in the making, recommends the UN implement new steps to cut off Isis’s access to money and guns.

The Isis arsenal, according to the UN assessment, includes T-55 and T-72 tanks; US-manufactured Humvees; machine guns; short-range anti-aircraft artillery, including shoulder-mounted rockets captured from Iraqi and Syrian military stocks; and “extensive supplies of ammunition”. One member state, not named in the report, contends that Isis maintains a motor pool of 250 captured vehicles.

Much of the Isis weapons stocks, particularly “state of the art” weaponry stolen from the US-backed Iraqi military, was “unused” before Isis seized it, the report finds. But some of the relatively complex weapons “may be too much of a challenge” for Isis to effectively wield or maintain.

Earlier this year, speculation focussed on Isis’s potential ability to produce chemical weapons after it seized Iraqi facilities that had contributed to Saddam Hussein’s illicit weapons programs, but the UN report casts doubt on the likelihood that Isis possesses the “capability to fully exploit material it might have seized”. Nor does the UN report believe that Isis can manufacture its own chemical or other weapons of mass destruction.

But at least one anonymous member state has provided information about “chemicals and poison-coated metal balls” placed inside Isis’s homemade bombs to maximize damage. In October, Kurdish forces defending the Syrian town of Kobani from Isis reported cases of skin blistering, burning eyes and difficulty breathing after the detonation of an Isis bomb.

The UN Security Council is expected to take up consideration of the report on Wednesday.

The report recommends the UN adopt new waves of sanctions designed to disrupt the well-financed Isis’s economic health. Significant among them is a call for states bordering Isis-controlled territory to “promptly seize all oil tanker trucks and their loads” coming in or going out.

While the report warns that Isis has alternate revenue sources, and does not predict that truck seizures can eliminate Isis’s oil smuggling money, it holds out hope that raising the costs to smuggling networks and trucking companies will deter them from bringing Isis oil to market.

To combat Isis’s ability to resupply its weapons stocks and launder money, the report recommends the UN mandate that no aircraft originating from Isis-held territory can land on airstrips in member states, and to prohibit flights into Isis-held territory. Exemptions would be made for humanitarian relief planes.

The report comes on the heels of an October report to the Security Council assessing that 15,000 fighters from 80 countries have flooded into Syria and Iraq to fight alongside Isis and other militant groups.

While still months off, the US has indicated it will intensify its fight against Isis, primarily in Iraq. After doubling the US troop commitment there, defense officials have said the US will bolster 12 Iraqi and Kurdish brigades, and may even join in the Iraqi fighting for key terrain, such as the borderlands between Syria and Iraq or the city of Mosul.