NBC News say these steel bollards were "sawed through", but there appears to be oxy-cutting slag on the cuts, especially on the far left (above)
The cuts appear too ragged in many parts to be from any type of saw - although the bottom section on the right does appear fairly clean - it still has some slag on it.
NBC News says:
The photo above seems to just be a concrete filled bollard, with maybe 3/8" steel, and it has been cut. But it seems misleading to say it was simply sawed through. It seems more likely it was done with a combination of tools. Perhaps oxy cutting was used to create the initial hole, allowing the concrete to be chipped away, and a saw inserted.
Oxy cutting sounds like it would need heavy equipment, but you can actually make a fairly cheap and light DIY version of a thermic lance, like this one by @NightHawkInLight
My own experience of cutting steel with "industrial tools" is from using an angle grinder with a cutting disk, and from using a reciprocating saw with a tungsten carbide blade. Both of these were on cheap battery-powered mobile tools.